activity report 2003-2008 · the nature of advanced materials is such that progress . depends...

ACTIVITY REPORT2003-2008

Summary 3 Foreword

4 History of RQMP

4 Administration

5 Research axis

6 Infrastructure

8 RQMP in numbers

10 Animation

11 Impact

12 Member profiles

47 Research projects

Edition and translation: Collective – RQMP members

Final editing: CoopDesign, Élise Saint-Jacques

Photos: Michel Caron, Robert Gagnon, Carol Gauthier, Simon Gélinas, Jean-Guy Paradis, Élise Saint-Jacques

Graphic design: CoopDesign

Circulation: 80 copies

This report is also published in French

Copyright: RQMP

ContactsDirector: Peter GrütterPhysics DepartmentMcGill UniversityMontreal, Canada

Phone: (514) 398-2567Fax: (514) 398-6526 Email: [email protected]

Coordinator: Élise Saint-Jacques

Phone: (514) 576-4511Fax: (514) 343-2071Email: [email protected]

Website: www.rqmp.ca

3 | RQMP | ACTIVITY REPORT 2003-2008

Foreword The nature of advanced materials is such that progress depends fundamentally on three kinds of rather distinct spe-cializations: the ability to make materials and structures, the ability to characterize and probe their properties, and the abil-ity to process and fabricate functioning devices and systems. Central to these three fundamentally experimental aspects of material science is a close linkage with theoretical expertise. The “Regroupement québécois sur les matériaux de pointe” (RQMP) was created to facilitate this convergence, bringing together world class researchers in growth, characterization, processing and theory to tightly integrate teaching and re-search from the fundamental to the applied.

There are many measures of excellence — the peer reviewed NSERC Discovery grant is one of the best overall proxies: our researcher’s Discovery grants are 20% above the average in their respective disciplines, several of our members are in the top 5%! It is thus not surprising that our members play central and leading roles in national and international research networks, thereby increasing RQMP’s visibility and network of collaborations. The RQMP enjoys priority recognition from participating Universities. RQMP now counts fifteen Canadian Research Chairs (CRC) and three James McGill Chairs (internal CRC at McGill University) within its 68 members, up from seven CRC when founded in 2003.

The training of students is a high priority tightly integrated with world-class research within RQMP. The multidisciplinary expertise of internationally recognized researchers, access to a range of infrastructures unparalleled in Canada, extensive networks of col-laborators combined with the organization of specific workshops, industrial visits and specialized summer schools all ensures that our students benefit from a unique training environment.

Several technologies developed by our researchers are now marketed by spin-offs com-panies: Quantiscript Nanotechnologies, QuantuModeling Inc., Atomistix Inc., LTRIM Technologies, NovaPlasma, MXT Inc. and Nanoacademics. Furthermore, by facilitat-ing access to its infrastructures, RQMP contributes to the development of many other technologies through contracts and research projects undertaken with its industrial, governmental and academic partners. The extent of technology transfer activities is documented by a steady increase of funding through grants obtained in partnership with industry.

The RQMP took up the challenge to bring together in one organizational structure re-searchers from many disciplines in order to enable and enhance outstanding research and training. This document is a summary of our first six years of existence and show-cases our extraordinary achievements in research, training and technology develop-ment. Building on these successes we look ahead to an exciting, productive and socially relevant future for RQMP.

Peter GrütterDirector of RQMPJames McGill Professor, Department of Physics, McGill University

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History of RQMPCreated in 2003, the “Regroupement québécois sur les matériaux de pointe” (RQMP) brings together Quebec’s three principal research centers in physics and the technol-ogy of materials: the Center for the Physics of Materials (CPM) of McGill University, the Thin Film Physics and Technology Research Center (GCM) at University of Montreal and Ecole Polytechnique de Montreal and the “Centre de recherche sur les proprié-tés électroniques des matériaux avancés” (CERPEMA) at Sherbrooke University. The RQMP is primarily supported by these four participating Universities along with major operating grants from the “Fonds québécois de recherche sur la nature et les tech-nologies” (FQRNT), the National Science and Engineering Research Council of Canada (NSERC) and NanoQuébec.

Close collaboration among the 68 members of RQMP — physicists, en-gineers and chemists, including specialists in experiments and theory — ensures that all skills and resources are focused on a common goal: the understanding, characterization and application of new materials and sys-tems. The expertise and interdisciplinary competencies of our researchers, as well as the exceptional infrastructure at their disposal, allows them to cover all aspects of research and development of materials, from synthe-sis and fabrication, modeling and characterization to the construction of prototype devices and operational systems. Distributed across four uni-versity campuses, these facilities are accessible to industrial users.

To stimulate and facilitate excellence in both research and training of highly skilled personnel RQMP organizes a series of networking activities ranging from specialized conferences, seminars and workshops. This includes the annual summer school, organized and run by the student community of RQMP, the “Regroupement québécois étudiant sur les ma-tériaux de pointe” (RQÉMP).

Administration• Executive Committee: Vincent Aimez, Université de Sherbrooke Yves-Alain Peter, École Polytechnique de Montréal Peter Grütter, McGill University (director 2007-2009) Hong Guo, McGill University Sjoerd Roorda, Université de Montréal Louis Taillefer, Université de Sherbrooke

• Organizing Committee of the “Grandes Conférences du Québec sur les Matériaux de Pointe”:

Guillaume Gervais, McGill University Alexandre Blais, Université de Sherbrooke Carlos Silva, Université de Montréal

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Research axisOur scientific program is based on close collaboration between theorists and experimentalists as well as the integration of fundamental and applied research. Here we list our five principal research areas, but emphasize there are strong overlaps between them.

1. Electronics and photonics of nanostructured materials The field of nanoelectronics and nanophotonics studies the processing, storage and transmission of information using electrons or photons by taking advantage of properties of matter on the nanoscale, which can be significantly different from those observed on macroscopic lengths. Research projects cover molecular electronics, quantum dots, quantum wires, heterostructures, superconductor-based nanostructures, photonic band gap materials and magnetoelectronics or “spintronics”.

2. Magnetism in material and systems Research projects in this area include the development of new particles and magnetic materials, transport studies on spin polarized electrons in semiconducting heterostructures, the investigation of magnetic cellular automata and the study of magnetism in quantum materials. Magnetic materials are increasingly being used not only in computer hard drives but in diverse applications ranging from small motors, magnetic separators, sensors and refrigerator components.

3. Quantum properties of materials This topic aims at discovering, understanding and controlling the behav-iour of correlated electrons and spins in new materials and structures, in order to reveal and understand unprecedented electronic properties such as high Tc superconductivity.

4. Advanced characterization and fabrication of novel materialsUnderstanding the structure of matter and the dynamics of its assembly is a key step in the design of new materials, where the position of every atom could have a significant impact on the physical properties of the final product. Whether synthesizing or characterizing materials, our researchers study the fundamental characteristics of the relevant technological sys-tems. The dynamic study of processes on the surface and at interfaces, the synthesis and fabrication of nano- and micro-structures, and the char-acterization of disordered mesoscopic systems are but a few examples of projects underway.

5. Properties of technological materials In order to transfer our knowledge to industrial applications, it is essential to under-stand the manufacturing processes of coatings and functional surfaces and how they relate to the desired material properties. Key to understanding how processing im-pacts functionality are in situ characterization during the thin film deposition. Several projects are designed to adapt manufacturing processes to achieve desired properties for thin film applications in fields such as photonics, microelectronics, aerospace, and pharmaceuticals.

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InfrastructureRQMP has developed a comprehensive infrastructure for advanced materials research. It is fair to say that materials scientists using the facilities are only limited by their imagina-tion. The research environment is not only conducive to so-phisticated and timely scientific progress but is ideal for the training of highly qualified personnel. Furthermore, our dem-onstrated capability to develop new tools and techniques, and to apply them to novel problems sets us apart from most other materials research centers.

Shared central facilitiesIn addition to having access to the specialized laboratories of the RQMP researchers, faculty and students also benefit from an extensive array of open-access central facilities equipped with leading-edge instrumentation. Teams of highly-qualified professionals and technicians ensure the optimal operation of the equipment as well as the transfer of expertise and know-how to the users. These facilities serve both the academic community and industrial users.

Materials synthesis and modificationVirtually any materials or structure can be created at RQMP fa-cilities, whether in bulk, thin film, or nanostructure form. Experts in thin film deposition develop hybrid techniques to achieve layers with predetermined micro/nanostructures. Exotic super-conducting single crystals are grown to investigate quantum behavior. Self-assembled organic layers are incorporated into flexible optoelectronic devices and biosensors. Ion beams are used to tailor the properties of materials for specific applica-tions and for investigating novel physics concept.

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Micro- and nanofabrication RQMP operates cleanrooms equipped with state-of-the-art tools for the fabrication of micro and nanostructures, electronic and photonic integrated circuits, sensors and ac-tuators, as well as hybrid structures. Our expertise in low-energy electron-beam lithog-raphy and in III-V semiconductor processing is internationally recognized.

Characterization and microanalysisCollectively, RQMP maintains and develops one of the most impressive infrastructures for the characterization of materials. The most advanced techniques for the chemical and physical characterization of surfaces, interfaces and thin films are all available within RQMP. Unique in Canada, the ion beam facility is internationally recognized for pioneering the development of analytical techniques. Furthermore, RQMP continues to be an international leader in the development of scanning probe microscopy and coher-ent x-ray scattering techniques. Our low-temperature physics infrastructure is the most complete in Canada. Our optical metrology and tribomechanics laboratory contributes to establishing international standards.

High-performance computingSeveral RQMP researchers play pivotal roles in Quebec’s main high performance com-puting consortia, CLUMEQ and RQCHP. In addition to providing access to mas-sively parallel supercomputing equipment, these consortia offer their expertise in paral-lel programming via training courses and workshops. The incomparable equipment avail-able is part of Canada’s major computer network, Compute Canada, and includes two of the most powerful com-puters in Canada (6.9 and 3 Tera Flops nodes), vectorial computers and shared mem-ory computers, allowing us to solve the most challenging materials science problems.

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RQMP in numbers

Financing As their work focus on priority areas for Quebec and Canada, RQMP researchers have obtained major grants from the Canadian Foundation for Innovation (CFI) since its inception in 1999. The RQMP has consequently access to the latest infrastructure and equipment, built up over the years, ensuring the researchers can adapt to the challenges and technological needs of tomorrow.

TABLE I - Equipment grants (K$)

2003 2004 2005 2006 2007 2008

Shared

CFI 1 6,309 19,145 0 0 3,542 1,142

NSERC 2 54 112 78 189 252 286

FQRNT 3 67 0 143 54 0 246

Other 0 0 0 0 1,624 0

Total 6,430 19,257 221 243 5,418 1,674

Individual

CFI 2,916 3,955 4,016 1,590 887 625

NSERC 33 313 213 571 717 536

FQRNT 109 84 158 78 212 44

Universities 110 90 220 509 0 0

Other 0 4,021 0 0 0 0

Total 3,168 8,463 4,607 2,748 1,816 1,205

1 Canadian Foundation for Innovation. CFI contributes 40% of the amount; 60% comes from other sources: Quebec government and Universities

2 Natural Sciences and Engineering Research Council of Canada3 Fonds de recherche sur la nature et la technologie du Québec

Continued investment from NSERC, NanoQuébec, FQRNT and from the participating universities has been essential for the maintenance and continuous improvement of the infrastructure and ensures a high level of competitiveness by the quality, by the variety of instrumentation available, and by the competence of our personnel.

Many of the research projects are funded as collaborations between several researchers (team projects financed by FQRNT) and as partnerships with industry. The increase in funds awarded to team research projects illustrates concerted efforts towards multidisciplinary and collaborative projects. In 2008 alone, our researchers were in-volved in more than twenty projects in partnerships with industrial members (NSERC Strategic and Collaborative Research and Development (CRD) Grants) in the fields of aeronautics, optics, nanotechnologies, sensors, semi-conductors, microelectronics, energy and biotechnology. In the life-science and biomedical sector a remarkable increase in grants has been obtained through collaborative projects financed by the Canadian Institute of Health Research (CIHR).

The average individual NSERC Discovery Grant, of each researcher, is 30% higher than the Canadian average in each respective discipline. Fifteen Canada Research Chairs and three James McGill chairs (the McGill equivalent to CRC tier I) provide leadership in key research sectors. When funds from all sources are compiled, each researcher has on average access to nearly $200,000 per year of operating funds.


2003 2004 2005 2006 2007 2008

Infrastructure

NSERC 646 743 658 659 595 401

NanoQuébec 1,485 1,311 1,141 992 798 1,005

MDEIE 4 0 0 0 0 1,603 1,603

Universities 471 528 545 522 555 430

CFI 0 13 13 134 184 160

Total 2,602 2,595 2,357 2,307 3,735 3,599

Operating-joint

NSERC (partnerships) 1,169 989 1,274 1,651 1,420 1,920

FQRNT (teams) 337 421 520 456 612 704

FQRNT (strategic clusters) 828 1,111 1,111 1,113 1,113 1,180

CIHR 5 135 261 653 926 711 593

FRSQ 6 0 0 0 0 12 30

Québec Gov. 0 34 52 54 60 48

Génome-Québec 133 133 44 0 0 115

Canada Gov. 89 97 219 405 444 487

VRQ 7 - NanoQuébec 565 283 0 0 0 0

VRQ - PROMPT 218 283 228 99 30 13

Total 3,474 3,612 4,101 4,704 4,402 5,090

Operating-individual

NSERC (discovery) 2,311 2,602 2,761 2,973 2,885 2,873

NSERC (others) 1,158 1,281 1,592 1,579 614 273

Research Chairs 565 784 875 898 772 787

Universities 116 236 424 329 199 25

FQRNT 38 76 116 122 135 141

CIFAR 8 97 121 172 172 172 248

Other 25 111 329 403 137 48

Total 4,310 5,211 6,269 6,476 4,914 4,395

TOTAL 10,386 11,418 12,727 13,487 13,051 13,084

4 Ministère du développement économique, de l’innovation et de l’exportation du Québec 5 Canadian Institute for Health Research6 Fonds de recherche en santé du Québec 7 Valorisation-Recherche Québec8 Canadian Institute for Advanced Research

StudentsOver 350 Master and PhD students constitute the core of the research teams; a highly skilled and motivated work-force, ready to meet the technological challenges of tomorrow.

TABLE II - Operating grants (K$)


AnimationOutside the individual research laboratory, exchanges, training courses, conferences and seminars are essential to push knowledge forward and to promote research. The RQMP invests the resources necessary to enable and organize such activities.

Regularly• Annual Meeting: Graduate students present their work in an informal setting, fostering

discussions and promoting new collaborations.

• RQÉMP Summer School: The student community organizes an annual summer school around topics of their choosing, to complement the training offered by the universities.

• “Grandes conférences du Québec sur les matériaux de pointe”: Twice a year, a renowned scientist is invited to give this prestigious lecture em-phasizing the status and future of fast developing sectors. Invitees have been: Mildred Dresselhaus and Steven M. Girvin (2005); Supriyo Datta and Michael Coey (2006); Christopher B. Murray and Zhi-Xun Shen (2007), Peter Littlewood and Allan H. Macdonald (2008). These visits are accompanied by lectures, question and answer sessions and meetings, to provide maximum interaction between the guest scientist and our members and students.

• Industrial visits: Organized in close collaboration with the RQÉMP, indus-trial visits aim at fostering better communication between the scientific com-munity and local industrial and governmental research centers (Dalsa, IBM, Canadian Space Agency, Industrial Materials Institute (NRC), Hydro-Quebec Research Institute).

Training workshops Graduate students are strongly encouraged to attend specialized work-shops, courses and summer schools, addressing new concepts and cutting edge technologies such as AFM microscopy, biochemical sensors or quan-tum materials.

International conferences and workshopsRQMP participates and helps organize events of international interest, often in partnership with other organizations. This contributes significantly to the transfer of knowledge and promotion of the results of its researchers. Exam-ples include: Flexibility in complex materials: glasses, amorphous and pro-teins, Sainte-Adèle (2005); High dimensional Partial Differential Equations in Science and Engineering, Montreal (2005), in collaboration with the Centre for Research in Mathematics (CRM) at the University of Montreal; First Canadian Workshop on Nanocarbon, Montreal (2005) in collaboration with GDR, France; Symposium on Molecular Imaging and Characterization, Montreal (2005); Con-ferences organized under the annual congress of ACFAS — The Association francophone pour le savoir: “Physics at the nanoscale,” Montreal (2006) and “Chemical and physical processes associated with surfaces, interfaces and nanostructures”, Quebec (2008); Organizational meeting for Quebec Synchro-tron Users, Montreal (2007); Symposia on Functional Coatings and Surface Engineering, Montreal (2005 and 2008), in collaboration with AVS; Thirteenth Canadian Semiconductor Technology Conference — CSTS2007, Montreal (2007) in partnership with The Canadian Institute for Microstructural Sciences (NRC); International Workshop on Nanomechanical Sensors, Montreal (2007); International summer school on Numerical methods for correlated systems in condensed matter, Magog (2008), in collaboration with CIFAR and PITT.


ImpactMore than one hundred awards and honors received by members of RQMP demonstrate their excellence and leadership. Examples are:

• Steacie Fellowships, NSERC (Grütter, Taillefer, Tremblay);

• Alfred P. Sloan Fellowship (Blais, Clerk, Gervais, Taillefer);

• Killam Research Fellowship, Canada Council for the Arts (Bandrauk, Guo, Sutton, Tremblay, Wertheimer);

• Rutherford Memorial Medal, Royal Society of Canada (Grant, Grütter);

• Brockhouse (Guo, Sutton, Taillefer) and Herzberg (Taillefer, Tremblay) medals, Canadian Association of Physicists;

• Urgel-Archambault award, Acfas (Bandrauk, Taillefer, Tremblay);

• and Marie-Victorin award, Quebec Government (Taillefer).

Several RQMP members bear the title of Fellow of prestigious societies:

• the Royal Society of Canada (Bandrauk, Grant, Grütter, Guo, Taillefer, Tremblay);

• the Royal Society of the United Kingdom (Sacher);

• the American Physical Society (Guo, Martel, Taillefer);

• the Institute of Electrical and Electronic Engineers (Yelon);

• the American Association for the Advancement of Sciences (Bandrauk);

• and the Canadian Institute for Advanced Research (Bourbonnais, Clerk, Fournier, Gervais, Grütter, Guo, Szkopek, Taillefer, Tremblay).

The work of our researchers has often been nominated by the journal Québec-Science to the top 10 discoveries of the year: Bandrauk (2004), Blais (2007), Martel (2006) and Taillefer (2003, 2007).

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13 Aimez, Vincent

13 Altounian, Zaven

14 Arès, Richard

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14 Badia, Antonella

15 Bandrauk, André

15 Barrett, Christopher

16 Beauvais, Jacques

16 Bennewitz, Roland

17 Bianchi, Andrea

17 Blais, Alexandre

18 Boone, François

18 Bourbonnais, Claude

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19 Caron, Laurent

19 Charlebois, Serge

20 Clerk, Aashish

20 Cochrane, Robert William

21 Côté, Michel

21 Côté, René

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22 Desjardins, Patrick

22 Drouin, Dominique

23 Dubé, Martin

23 Dubowski, Jan

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24 Fournier, Patrick

24 Francoeur, Sébastien

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25 Gervais, Guillaume

25 Grant, Martin

26 Grütter, Peter

26 Guenat, Olivier

27 Gujrathi, Subhash

27 Guo, Hong

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28 Hilke, Michael

28 Houdayer, Alain

J

29 Jandl, Serge

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29 Kilfoil, Maria

30 Klemberg-Sapieha, Jolanta

L

30 Lennox, Bruce

31 Leonelli, Richard

31 Lewis, Laurent

32 Lupien, Christian

M

32 Maciejko, Romain

33 Martel, Richard

33 Martinu, Ludvik

34 Masut, Remo

34 Ménard, David

35 Meunier, Michel

35 Mi, Zetian

36 Morris, Denis

36 Mousseau, Normand

N

37 Nigam, Nilima

P

37 Peter, Yves-Alain

38 Poirier, Mario

R

38 Rochefort, Alain

39 Roorda, Sjoerd

39 Ryan, Dominic

S

40 Sacher, Edward

40 Santato, Clara

41 Schiettekatte, François

41 Sénéchal, David

42 Silva, Carlos

42 Siwick, Bradley J.

43 Sutton, Mark

43 Szkopek, Thomas

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44 Taillefer, Louis

44 Tremblay, André-Marie

V

45 Vinals, Jorge

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45 Wertheimer, Michel

46 Wiseman, Paul

Y

46 Yelon, Arthur

member profiles12

| RQMP | MEMbERs

Research interests

Vincent Aimez is a founding member of the Centre de Recherche en Nanofabrica-tion et en Nanocaracterisation CRN² at the University of Sherbrooke where he played a crucial role in setting up rapid prototyping capabilities for optoelectronics device micro-nanofabrication processes. He is working on a wide variety of mate-rial systems including Silicon/SOI, InP, GaAs as well as GaN III-V heterostructures.

He has recently launched a vigorous research activity focused on the fabrication of hybrid photonic devices based on III-V membrane bonding onto glass/silica substrates. He is also heavily involved in the fabrication high efficiency multiple junction solar cells using newly developed processes for device passivation and etching.

He is collaborating with other researchers targeting applications from renewable energy to monolithically integrated telecom devices as well as biophotonic sensor devices for healthcare.

Selected publications

• “Nonlinear scattering and trapping by local photonic potentials”, Y. Linzon, R. Morandotti, M. Volatier, V. Aimez, R. Arès and S. Bar-Ad, Physical Review Letters 99, 133901 (2007).

• “Optical modes at the interface between two dissimilar discrete meta-materials”, S. Suntsov, K. G. Makris, D. N. Christodoulides, G. I. Stegeman, R. Morandotti, M. Volatier, V. Aimez, R. Arès, C.E. Rüter and D. Kip, Optics Express 15, 4663 (2007).

• “Bandgap tuning of InAs/InP quantum sticks using low-energy ion-implantation-induced intermixing”, B. Salem, V. Aimez, D. Morris, A. Turala, P. Regreny and M. Gendry, Applied Physics Letters 87, 24115 (2005).

• “Hybridization of III-V semiconductor membranes onto ion-exchanged waveguides”, M. Nannini, E. Grondin, A. Gorin, V. Aimez and J.E. Broquin, IEEE Journal of selected Topics in Quantum Electronics, Special issue on

Integrated Optics 11, 547 (2005).

• “Low energy ion implantation induced quantum well intermixing”, V. Aimez, J. Beauvais, J. Beerens, D. Morris, H.S. Lim and B.S. Ooi, IEEE Journal of selected Topics in Quantum Electronics 8, 870 (2002).

Professionnal affiliations

Institute of Electrical and Electronics Engineers (IEEE)Institute of Physics (IOP)

Research keywords

Nanofabrication, microfabrication, optoelectronics, biophotonics

Research interests

My research interests are in the physics of novel materials. They fall into the following general four categories:

1. Metallic Glasses. Electronic transport properties, superconductivity, phase change materials.

2. Magnetocaloric materials. In particular those compounds and alloys that exhibit a giant magnetocaloric effect.

3. Nanomagnetism. This involves hard magnetic materials with controlled nano-structures, magnetic multilayers, spin valves, and magnetic nanocomposites.

4. First principles density functional theory calculations using the muffin-tin orbital method to determine the electronic structure and magnetic ground state properties of magnetic compounds.


• “Structure and magnetic properties of bulk nanocrystalline SmCo6.6Nb0.4 permanent magnets”, M. Yue, J.X. Zhang, L.J. Pan, X.B. Liu and Z. Altounian,

Appl. Phys. Lett. 90, 242506 (2007).

• “Magnetic states and magnetic transition in RCo2 Laves phases”, X.B. Liu and Z. Altounian, J. Phys.-Cond. Matter 18, 5503 (2006).

• “The structure and large magnetocaloric effect in rapidly quenched LaFe11.4Si1.6 compounds”, X.B. Liu, Z. Altounian and G.H. Tu, J. Phys.-Cond. Matter 16, 8043 (2004).

• “Pd polarization and interfacial moments in Pd-Fe multilayers”, L. Cheng, Z. Altounian and D.H. Ryan, Phys. Rev. B 69, 144403 (2004).

• “Electronic transport properties in amorphous and crystalline FeZr2 examined via the density of states”, M. Dikeakos, Z. Altounian and M. Fradkin, Phys. Rev. B 70, 024209 (2004).

Research keywords

Magnetocaloric materials, density functional theory, nanomagnetism, metallic glasses, magnetic multilayers

Name: Vincent Aimez Affiliations: Professor, Department of Electrical and Computer Engineering; Director, Centre de Recher-che en Nanofabrication et en Nanocaractérisation (CRN2); Member, Centre d’Excellence en Génie de l’Information (CEGI), Université de Sherbrooke Diploma: Ph.D., Electrical Engineering, 2000, Université de Sherbrooke, CanadaEmail: [email protected]: www.crn2.ca / www.cegi.ca

Name: Zaven Altounian Affiliation: Professor, Department of Physics, McGill UniversityDiploma: Ph.D., Physics, 1979, McMaster University, Hamilton, Ontario, CanadaEmail: [email protected]: www.physics.mcgill.ca/

13 | RQMP | MeMbeRs

AIMeZ V. ALTOUNIAN Z.

Research interests

At the Laboratoire d’Épitaxie Avancée (LÉA), we explore epitaxial deposition methods of semiconductor layers. Our studies cover the field from the three following research axes:

Advanced Tools: By developing the deposition technique of Chemical Beam Epitaxy (CBE), a modified version of the more established Molecular Beam Epitaxy (MBE) technique, we aim to design a new generation of CBE tools, which will surpass all other systems in material quality, process versatility, and cost of ownership. Using state-of-the-art CAD/CAM techniques and numerical simula-tions to optimize the components, we build all subsystems from the ground up, ranging from the gas handling and injection systems, UHV enclosure, computer controller, and sample handling/heating systems.

Advanced Processes: Through in-situ measurements, we improve the deposition processes allowing lateral control of the growth, as well as real-time monitoring or modification of the surface. These processes will enable new disruptive tech-nologies for the fabrication of complex semiconductor devices such as integrated systems in telecommunications, environmental, medical or defense applications.

Advanced Materials: We explore techniques of deposition of new materials using CBE as the main technique, focusing on semiconductors of the III-V family (III-V, III-N, III-Sb). We are also planning to combine different deposition techniques to fabricate devices, namely hydride vapor phase epitaxy (HVPE) or oxide-MBE with CBE.


• “Electronic Optical modes at the interface between two dissimilar discrete meta-materials”, S. Suntsov, K.G. Makris, D.N. Christodoulides, G.I. Stegeman, R. Morandotti, M. Volatier, V. Aimez, R. Arès, C.E. Rüter and D. Kip, Optics Express 15, 4663 (2007).

• “Determination of structural parameters in heterojunction bipolar transistors by x-ray diffraction with (002) reflection”, A. Shen, E.M. Griswold, G. Hillier, L. Dang, A. Kuhl, R. Arès, D. Clark and I.D. Calder, J. Vac. Sci. Technol. A 20, 1011 (2002).

• “Calibrated scanning spreading resistance microscopy profiling of carriers in III-V structures”, R. P. Lu, K. L. Kavanagh, S. J. Dixon-Warren, A. Kuhl, A. J. SpringThorpe, E. Griswold, G. Hillier, I. Calder, R. Arès and R. Streater, J. Vac. Sci. Technol. B 19, part 4, 1662 (2001).

• “Effects of Growth Rate on Surface Morphology of Heavily Carbon-Doped InGaAs”, A. Kuhl, R. Arès and R. Streater, J. Vac. Sci. Technol. B 19, part 4, 1550 (2001).

Research keywords

Chemical beam epitaxy, ultra-high vacuum, in-situ monitoring, III-V semiconductors, nanostructures

Name: Richard Arès Affiliation: Associate professor, Department of Mechanical Engineering; Member, Centre de Recherche en Nanofabrication et en Nanocaractéri-sation (CRN2) and Centre d’Excellence en Génie de l’Information (CEGI), Université de SherbrookeDiploma: Ph.D., Physics, 1998, Simon Fraser University, CanadaEmail: [email protected]: www.gel.usherbrooke.ca/crn2/pages_ personnel/ares/accueil_en.htm

Research interests

My research group is involved in organic thin film and surface chemistry research. Our work focuses on developing a fundamental understanding and control of the factors that drive the molecular assembly of highly-structured, ultrathin organic films, and on exploiting such films for a variety of key objectives, including nano-scale patterning and templating in support of nanofabrication and the production of structured biomimetic surfaces, either as model systems for research on biological function or as functional coatings for biomedical devices. Our current approaches to achieving solid-supported films of well-defined lateral organization and phase structure are based on the self-assembly of ω-functionalized alkane-thiols on gold surfaces and on the Langmuir-Blodgett (LB) or Langmuir-Schaefer (LS) deposition of lipid monolayers formed at the air/water interface. These films are used to address important and timely problems in nanofabrication, membrane biophysics, and biomaterials chemistry: lipid microdomain formation in biological cell membranes, preparation of laterally nanostructured surfaces, and design of biocompatible coatings.


• “Electrochemical Surface Plasmon Resonance Investigation of Dodecyl Sulfate Adsorption to Electroactive Self-Assembled Monolayers via Ion-Pairing Interactions”, L.L. Norman and A. Badia, Langmuir 23, 10198 (2007).

• “Effect of Molecular Weight on the Exponential Growth and Morphology of Hyaluronan/Chitosan Multilayers: A Surface Plasmon Resonance Spectroscopy and Atomic Force Microscopy Investigation”, P. Kujawa, P. Moraille, J. Sanchez, A. Badia and F. M. Winnik, J. Am. Chem. Soc. 127, 9224 (2005).

• “Enzymatic Lithography of Phospholipid Bilayer Films by Stereoselective Hydrolysis”, P. Moraille and A. Badia, J. Am. Chem. Soc. 127, 6546 (2005).

• “Nanomechanical Cantilever Motion Generated by a Surface-Confined Redox Reaction”, F. Quist, V. Tabard-Cossa and A. Badia, J. Phys. Chem. B 107, 10691 (2003).

• “Nanoscale Stripe Patterns in Phospholipid Bilayers Formed by the Langmuir-Blodgett Technique”, P. Moraille and A. Badia, Langmuir 19, 8041 (2003).

Honors and awards

2006: Canada Research Chair on Ultrathin and Membrane Organic Structures (Tier II)

2004: Canadian National Committee/IUPAC Travel Award2002: Cottrell Scholar Award, Research Corporation, USA2000: Scholar of Programme stratégique de professeurs-chercheurs, Fonds FCAR1999: Research Innovation Award, Research Corporation, USA

Professional affiliations

American Chemical SocietyChemical Institute of Canada

Research keywords

Surfaces and interfaces, organic ultrathin films, scanning probe microscopy

Name: Antonella Badia Affiliations: Associate Professor, Department of Chemistry, Université de Montréal; Associate Director, FQRNT Center for Self-Assembled Chemical Structures; Canada Research Chair on Ultrathin and Membrane Organic StructuresDiploma: Ph.D., Chemistry, 1996, McGill University, Montreal, CanadaEmail: [email protected]: www.esi.umontreal.ca/~badiaa/homepage/badia_index.html

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ARÈs R. bADIA A.

Research interests

1. Advanced numerical methods for computational chemistry with application to molecular photonics- i) nonperturbative Time Dependent Density Functional Theory, ii) Maxwell-Schroedinger and Maxwell-Dirac Equations for nonpertur-bative laser-molecular interactions beyond Born-Oppenheimer.

2. Nonperturbative Quantum Control of matter with Intense Ultrafast Laser Pulses.

3. Nonperturbative Molecular Nonlinear Optics such as High Order Harmonic Generation

4. Attosecond Science — The Next Frontier!


• “A Numerical Maxwell-Schroedinger Model for Intense Laser-matter Interaction and Propagation”, E. Lorin, S. Chelkowski and A. D. Bandrauk, Comput. Phys Commun. 177, 908 (2007).

• “Normal Form Transition State Theory for Laser Controlled Reactions”, S. Kawai, A. D. Bandrauk and T. Uzer, J. Chem. Phys. 126, 164306 (2007).

• “Laser Phase Control of High Order Harmonic Generation at Large Distance”, A. D. Bandrauk, S. Barmaki and G. Lagmago-Kamta, Phys Rev Lett. 98, 013001 (2007).

• “Chirped Attosecond Photoelectron Spectroscopy”, G. L. Yudin, A. D. Bandrauk and P. B. Corkum, Phys. Rev. Lett. 96, 063002 (2006).

• “Coherent Control of Harmonic Generation in Super Lattices”, K. Pronin and A. D. Bandrauk, Phys. Rev. Lett. 97, 020602 (2006).

Honors and Awards

2007: J. C. Polanyi Prize – NSERC (with P. B. Corkum, NRC)2007: Fellow – Humboldt Foundation (Germany)2005: Urgel Archambault Prize – ACFAS/FQRNT2003: Fellow of the American Association for the Advancement of Science2002: Canada Research Chair in Computational Chemistry and Molecular

Photonics (Tier I)2001: J. C. Polanyi Award – Chemical Institute of Canada1999: Fellow – Japan Society for Promotion of Science1992: Fellow – Royal Society of Canada1987: Fellow – Chemical Institute of Canada1982: Killam Fellow – Canada Council1968: NATO Research Fellow – Oxford University, UK

Professional Associations

Canadian Association of Physicists (CAP)Canadian Society of Chemistry (CSC)Association canadienne-française pour l’avancement des sciences (ACFAS)American Chemical Society (ACS)American Physical Society (APS)Optical Society of America (OSA)Society for Industrial & Applied Mathematics (SIAM)Canadian Association of Theoretical Chemists (CATC)

Research Key words

Computational chemistry, laser chemistry, nonlinear molecular optics, ultrafast intense laser science, attosecond science

Research interests

The approach to research taken by the Barrett Group is to apply aspects of the field of optics and photonics to the new technique of self-assembly of multi-layer thin films, built from dilute solution. This novel approach to bio-optical interfaces and de-vices will concentrate on the communication between light signals, and the bulk and surface structure of the films. Specifically, this program of research is an investiga-tion of the optical and surface properties of thin films of novel polymers. The optical and surface properties are interrelated in these materials, allowing studies both of how light can be used to gather information about surfaces and structures, and how light can be used to influence surface and structural properties. This will be accom-plished with polymer materials which incorporate both light-absorbing photo-active groups (azobenzene chromophores), and water-soluble ionic groups (electrolytes).

These azo-polyelectrolytes are thus very interesting as they have the unique capability to be both addressed with lasers as electro-optic materials (useful for information storage, holography, and signal processing devices for example), yet can also be self-assembled into structures on the molecular lengthscale, using the + and - ionic groups as building blocks. Furthermore, the aqueous nature of the materials will be used to explore compatibility between biological systems and more traditional electronic and photonic devices. An eventual goal of this research is to demonstrate that these bio-compatible films can be interfaced with current technologies and be used as bio-active sensors, to permit information processing systems to communicate directly with natural systems.


• “Photo-Mechanical Effects in Azobenzene-Containing Soft Materials”, C.J. Barrett, T. Ikeda, K.G. Yager and J. Mamiya,

Soft Matter 3, 1249 (2007).

• “Novel Photoswitching using Azobenzene Functional Materials”, K.G. Yager and C.J. Barrett,

Journal of Photochemistry and Photobiology A: Chemistry 182, 250 (2006).

• “Light-Induced Reversible Volume Changes in Thin Films of Azo Polymers: the Photo-Mechanical Effect”, O.M. Tanchak and C.J. Barrett, Macromolecules 38, 10566 (2005).

• “Swelling Behavior of Hyaluronic Acid/Polyallylamine Hydrochloride Multilayer Films”, S.E. Burke and C.J. Barrett,

Biomacromolecules 6, 1419 (2005).

• “Physico-Chemical Properties of Multilayers of Weak Polyelectrolytes”, S.E. Burke and C.J. Barrett,

Pure and Applied Chemistry 76, 1387 (2004).

Honors and awards

2006: Japan Society for the Promotion of Science (JSPS) Visiting Professorship2005: ISI Essential Science Indicator Citation Index Highly Cited Paper “Fast-Moving

Research Front” for all of Biochemistry and Biology, 04/05, 20052003: Royal Society of Canada PAGSE “Leader of Tomorrow”2000: FCAR Strategic Professor-Researcher1997: NSERC Postdoctoral Fellowship1996: Canadian Society for Chemistry Graduate Award in Macromolecular Science 1996: Canadian Association of Physicists Newport Graduate Award in Optical Sciences


Canadian Association of Physicists (CAP)American Chemical Society (ACS)American Physical Society (APS)Materials Research Society (MRS)The Chemical Institute of Canada (CIC)American Association for the Advancement of Science (AAAS)SPIE

Research keywords

Polyelectrolyte multilayers, azobenzene photochemistry, surface science, optical patterning

Name: Andre D. Bandrauk, Ph. D., FRSC, FAAASAffiliations: Professor of Theoretical and Computa-tional Chemistry, Department of Chemistry, Université de Sherbrooke; Associate member – Centre de Recherches Mathématiques – CRM (Montreal), Humboldt Research Fellow, (Free University Berlin); Canada Research Chair in Computational Chemistry and Molecular Photonics Diploma: Ph.D., Chemical Physics, 1968, McMaster University, Ontario, CanadaEmail: [email protected]: http://pages.usherbrooke.ca/adbandrauk

Name: Christopher Barrett Affiliations: Associate Professor, Department of Chemistry, McGill University; McGill Institute for Advanced Materials; Canadian Institute for Neutron Scattering, National Research Council of Canada; FQRNT Centre for Self-Assembled Chemical Structures, Department of Physics, McGill University Diploma: Ph.D., Chemistry, 1997, Queen’s University, Canada Email: [email protected]: www.barrett-group.mcgill.ca

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bANDRAUK A. bARReTT C.

Research interests

For more than 15 years, Jacques Beauvais has centered his research activities on the development of nanofabrication techniques, in particular the use of electron beam lithography for the fabrication of nanostructures integrated in advanced electronic and photonic devices.

His work has led to 6 patents, and a technology transfer in the case of a spin-off technology company. He is especially interested in studying new properties arising from the nanometric scale of the components realized in his laboratory. Over the past 10 years, his work focused on the development of techniques combining lithography and self-assembly to fabricate metallic nanostructures, on the development of new resists for electron-beam lithography, and on the realization of nanometer scale metallic thin film arrays as essential components of surface plasmon resonance-based biosensors. Invited in Spain in 2005 to present new techniques of nanolithography, he also developed a model to study the ultimate limits of the electron beam lithography techniques. Several large companies involved in the technology of the semiconductors (in particular STMicroelectronics and the Sematech consortium) use the results of this model.


• “Single-electron transistors with wide operating temperature range”, C. Dubuc, J. Beauvais and D. Drouin, Appl. Phys. Lett. 90, 113104 (2007).

• “Enhancement of quantum well intermixing on InP/InGaAs/InGaAsP hetero-structures using titanium oxide surface stressors to induce forced point defect diffusion”, A. François, V. Aimez, J. Beauvais, M. Gendry and P. Regreny, Appl. Phys. Lett. 89, 164107 (2006).

• “Uniform 1-Dimensional Arrays of Tunable Gold Nanoparticles with Tunable Inter-particle Distances”, M. Corbierre, J. Beerens, J. Beauvais and R.B. Lennox, Chemistry of Materials 18, 2628 (2006).

• “Nano patterning on optical fiber and laser diode facet with dry resist”, P. Kelkar, J. Beauvais, E. Lavallée, D. Drouin, M. Cloutier, D. Turcotte, Pan Yang, Lau Kien Mun, R. Legario, Y. Awad and V. Aimez, J. Vac. Sci. Technol. A 22, 743 (2004).

• “Method of producing an etch-resistant polymer structure using electron beam lithography”, E. Lavallée, J. Beauvais, D. Drouin and M. Cloutier, USA Patent #6,777,167 (2004).


Institute of Electrical and Electronics Engineers (IEEE)Ordre des Ingénieurs du Québec (OIQ)

Research keywords

Nanolithography, nanofabrication, microfabrication, electronics, photonics

Research interests

In our research we aim to establish an understanding of mechanical properties of surfaces from a microscopic perspective. Towards this goal, the group performs cutting-edge experiments which are centered around, but not limited to high-resolution force microscopy. In order to contribute novel techniques, results, and insights we develop and build most of our instrumentation ourselves.

We are interested in the fundamental processes of friction, wear, and plasticity. Experimentally, these processes manifest themselves as atomic jumps in lateral or normal force signals. The correlation of force measurements and high-resolution imaging allows for a quantitative description of the elementary steps of dissipation and deformation, in direct comparison to atomistic simulations.

The experiments are carried out under well-defined conditions in ultra-high vacu um or in an electrochemical cell. We also have a strong interest in the sur-face science of insulators, in particular in self-organized nanometer-scale struc-ture which can serve as templates for the growth of functional nanostructures.


• “Asymmetry in the reciprocal epitaxy of NaCl and KBr”, S. Maier, O. Pfeiffer, Th. Glatzel, E. Meyer, T. Filleter and R. Bennewitz, Phys. Rev. B 75, 195408 (2007).

• “Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts”, A. Socoliuc, E. Gnecco, S. Maier, O. Pfeiffer, A. Baratoff, R. Bennewitz and E. Meyer, Science 313, 207 (2006).

• “Structured surfaces of wide-band gap insulators as templates for overgrowth of adsorbates”, R. Bennewitz, J. Phys.: Condens. Matter 18, R417 (2006).

• “Atomic-scale yield and dislocation nucleation in KBr”, T. Filleter, S. Maier and R. Bennewitz, Phys. Rev. B 73, 155433 (2006).

• “Fluctuations and jump dynamics in atomic friction experiments”, S. Maier, Yi Sang, T. Filleter, M. Grant, R. Bennewitz, E. Gnecco and E. Meyer, Phys. Rev. B 72, 245418 (2005).

Honors and awards

2004: Canada Research Chair in Experimental Nanomechanics (Tier II)


American Vacuum SocietyCanadian Association of PhysicistsAmerican Physical SocietyDeutsche Physikalische Gesellschaft

Research keywords

Nanoscience, scanning probe microscopy, nanomechanics, surface science

Name: Jacques Beauvais Affiliations: Professor, Department of Electrical and Computer Engineering; Vice-principal for research; Member, Centre de Recherche en Nanofabrica-tion et en Nanocaractérisation (CRN2) and Centre d’Excellence en Génie de l’Information (CEGI), Université de SherbrookeDiploma: Ph.D., Physics, 1990, Université d’Ottawa, Ottawa, CanadaEmail: [email protected]: www.gel.usherbrooke.ca/crn2/pages_ personnel/beauvais/accueil.htm

Name: Roland Bennewitz Affiliations: Assistant Professor, Department of Physics, McGill University; Canada Research Chair in Experimental Nanomechanics; Since 2008: Leibniz Institute for new materials, Saarbrücken, GermanyDiploma: Ph.D., Physics, 1997, Freie Universitat Berlin, GermanyEmail: [email protected]: www.physics.mcgill.ca/~roland/

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beAUVAIs j. beNNewITZ R.

Research interests

The Bianchi Research Group grows and characterizes novel intermetallic compounds, mainly through flux and vapor transport, for addressing fundamental questions in spintronic materials and unconventional superconductors.

We are taking part in the world-wide scientific and technological efforts to take advantage of spin as well as charge degrees of freedom for information transmis-sion, manipulation, and storage. In analogy to conventional electronics, this field of development has been labeled spintronics. Spintronic materials rely on an intricate interplay between the spin and charge degrees of freedom. The aim of our research is to answer the central challenge to engineering spintronic devices, which is the lack of a clear understanding of how magnetic moments are formed in magnetic semiconductors: As it is these very moments that enable the functionality.

In unconventional superconductors, we are using small angle neutron scattering (SANS) for probing the superconducting state in high magnetic fields and low temperatures in collaboration with researchers in Switzerland. While in s-wave superconductors, quasiparticle excitations are confined to the vortex cores allowing a quasiclassical treatment, an entirely new regime becomes accessible in unconventional superconductors where a full quantum mechanical treatment of the interaction between quasiparticles and the magnetic field of the vortices is required.


• “Superconducting Vortices in CeCoIn5: Toward the Pauli-Limiting Field”, A. D. Bianchi, M. Kenzelmann, L. DeBeer-Schmitt, J. S. White, E. M. Forgan, J. Mesot, M. Zolliker, J. Kohlbrecher, R. Movshovich, E. D. Bauer, J. L. Sarrao, Z. Fisk, C. Petrovic and M. R. Eskildsen, Science 319, 177 (2008).

• “Magneto-Optical Evidence of Double Exchange in a Percolating Lattice”, G. Caimi, A. Perucchi, L. Degiorgi, H. R. Ott, V. M. Pereira, A. H. Castro Neto, A. D. Bianchi and Z. Fisk, Phys. Rev. Lett. 96, 016403 (2006).

• “Possible Fulde-Ferrell-Larkin-Ovchinnikov superconducting state in CeCoIn5”, A. Bianchi, R. Movshovich, C. Capan, P.G. Pagliuso and J. L. Sarrao, Phys. Rev. Lett. 91, 187004 (2003).

• “Avoided antiferromagnetic order and quantum critical point in CeCoIn5”, A. Bianchi, R. Movshovich, I. Vekhter, P. G. Pagliuso and J. L. Sarrao, Phys. Rev. Lett. 91, 257001 (2003).

• “First-order transition from a Kondo insulator to a ferromagnetic metal in single crystalline FeSi1−xGex”, S. Yeo, S. Nakatsuji, A. D. Bianchi, P. Schlottmann, Z. Fisk, L. Balicas, P. A Stampe and R.J. Kennedy, Phys. Rev. Lett. 91, 046401 (2003).

Honors and awards

2007: Canada Research Chair in Novel Materials for Spintronic Applications (Tier II)


American Physical Society

Research keywords

Superconductivity, spintronics, strongly correlated materials, crystal growth

Research interests

Blais’ research is focused on the physics of quantum information and on mesoscopic systems showing quantum mechanical phenomenon on large scales. Working in close collaboration with experimental groups, he his interested in finding new ways to use the mesoscopic systems in the context of quantum information processing. In particular, he his interested in superconducting qubits and the link between these solid-state systems and quantum optics.


• “Resolving photon number states in a superconducting circuit”, D. I. Schuster, A. A. Houck, J. A. Schreier, A. Wallraff, J. M. Gambetta, A. Blais, L. Frunzio, B. Johnson, M. H. Devoret, S. M. Girvin and R. J. Schoelkopf, Nature 445, 515 (2007).

• “Quantum information processing with circuit quantum electrodynamics”, A. Blais, J. M. Gambetta, A. Wallraff, D. I. Schuster, S. M. Girvin, M. H. Devoret and R. J. Schoelkopf, Phys. Rev. A 75, 032329 (2007).

• “Qubit-photon interactions in a cavity: Measurement-induced dephasing and number splitting”, J. Gambetta, A. Blais, D. Schuster, A. Wallraff, L. Frunzio, R.-S. Huang, J. Majer, M. H. Devoret, S. M. Girvin and R. J. Schoelkopf, Phys. Rev. A 74, 042318 (2006).

• “Sideband Transitions and Two-Tone Spectroscopy of a Superconducting Qubit Strongly Coupled to an On-Chip Cavity”, A. Wallraff, D. I. Schuster, A. Blais, J. Gambetta, J. Schreier, L. Frunzio, M. H. Devoret, S. M. Girvin, and R. J. Schoelkopf, Phys. Rev. Lett. 99, 050501 (2007).

• “Protocol for universal gates in optimally biased superconducting qubits”, C. Rigetti, A. Blais and M. Devoret, Phys. Rev. Lett. 94, 240502 (2005).

Honors and awards

2008: Alfred P. Sloan Fellowship 2007: Top Ten Discoveries of the Year, magazine Québec Science 2004: NSERC Doctoral Prize, 2004


Canadian Association of PhysicistsAmerican Physics Society

Research keywords

Superconducting qubits, quantum optics, mesoscopic systems, quantum information

Name: Andre Daniele Bianchi Affiliation: Assistant Professor, Department of Physics, Université de Montréal; Canada Research Chair in Novel Materials for Spintronic ApplicationsDiploma: Ph.D., Natural Sciences, 1999, Swiss Federal Institute of Technology Zurich, Switzerland Email: [email protected]: www.phys.umontreal.ca/~andrea_bianchi/

Name: Alexandre Blais Affiliations: Assistant Professor, Department of Physics, Université de Sherbrooke; Member of the CIFAR Quantum information processing and Quantum materials programs; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Physics, 2002, Université de Sherbrooke, CanadaEmail: [email protected]: www.physique.usherbrooke.ca/blais/

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bIANChI A.D. bLAIs A.

Research interests

The «Microwave Electronics Laboratory», established in 1999 by François Boone, addresses the design, fabrication and characterization of microelectronic devices for telecom applications. Research projects are interdisciplinary; most of them involving photonics, electronics, materials science, signal analysis and millimeter wavelength imaging.

One particular aspect of the research is the development of microwave imaging devices with potential applications in diverse fields such as medicine, safety, manufacturing processes and pharmacology. In particular, we exploit the capacity of a microwave or millimeter radiometric systems to form images in the presence or absence of visible light (i.e. at day or night) and in any atmospheric condition, including rain, snow, fog, clouds, smoke and sandstorms, since electromagnetic radiation, contrary to optical radiation, is not very sensitive to these phenomena.

Another aspect of our research is the development of modeling and analysis tools to design new microwaves and millimeter components of complex systems, such as passive microwave image formation.


• “Design and Analysis of Microstrip-Line-Coupled NRD Guide Filter Based on Integral Equation Techniques”, D. Li, F. Boone and K. Wu International Journal of RF and Microwave Computer

–Aided Engineering (In press 2008).

• “Iterative Design Techniques for All-Pole Dual-Bandpass Filters”, D. Deslandes and F. Boone, Microwave and Wireless Components Letters,

IEEE 17.11, 775–777 (2007).

• “ An Electric Field Integral Equation Approach for Accurate Modeling of Transmission Loss Properties and Leakage Phenomena in NRD–Guide of Arbitrary Cross Section”. D. Li, F. Boone and K. Wu, International Journal of RF and Microwave Computer

–Aided Engineering 17.3, 360–366 (2007).

• “ Design and calibration of a large open-ended coaxial probe for the measurement of the dielectric properties of concrete”, F. Boone, IEEE Transactions on Microwave Theory and Techniques

(submitted March 2007).

• “ Mode conversion and design consideration of integrated nonradiative dielectric (NRD) components and discontinuities”, F. Boone and K. Wu, IEEE Transactions on Microwave Theory and Techniques 48.4,

482 (2000).

Professional affiliation

IEEE Microwave Theory and techniques society

Research keywords

Microwave and millimetric circuits, characterization by microwave

Research interests

In the group of Prof Bourbonnais, we are interested in the theoretical description of the various states of the matter, met in the systems strongly correlated with dimensionnality reduced like the organic drivers and superconductive. This study covers the vast field of the liquids known as quantum which characterize the physics of the systems with unidimensional N-bodies like the liquid of Luttinger and insulator of Mott and their complex transformation towards ordered states of three-dimensional physics. A particular interest is related to the origin of certain exotic phases such organic supraconductivity and of its close link with magnetism and in a more general way with the modulated phases electronic or structural. A significant part of our activity is dedicated to the development and the refine-ment of methods of quantum statistical physics such group of renormalisation which makes it possible to describe in a controlled way, to even predict the existence of new quantum states in the strongly correlated systems with reduced dimensionnality.


• “Role of Interchain Hopping in the Magnetic Susceptibility of Quasi-One-Dimensional Electron Systems”, Y. Fuseya, M. Tsuchiizu, Y. Suzumura and C. Bourbonnais, J. Phys. Soc. Jpn. 76, 014609 (2007).

• “Effect of interchain frustration in quasi-one-dimensional conductors at half-filling”, M. Tsuchiizu, Y. Fuseya, Y. Suzumura and C. Bourbonnais, Journ. of Low Temp. Phys. 142, 651 (2006).

• “Superconducting pairing and density-wave instabilities in quasi-one-dimen-sional conductors”, J. C. Nickel, R. Duprat, C. Bourbonnais and N. Dupuis, Phys. Rev. B 73, 165126 (2006).

• “Superconductivity and antiferromagnetsim in quasi-one-dimensional organic conductors”, N. Dupuis, C. Bourbonnais and J. C. Nickel, Fizika Nizkikh Temperatur 32, 505 (2006);

Low Temperature Physics 32, 380 (2006).

• “Effect of interchain quasi-one-dimensional conductors at half-filling”, M. Tsuchiizu, Y. Suzumura and C. Bourbonnais, Proc. of the international conference of highly frustrated magnetism,

Osaka, August, 2006. J. Phys.: Condens. Matter 19, 145228 (2007).

Honors and awards

2005, 2000, 1991: Invited professor, Laboratoire de Physique des Solides d’Orsay, France

2004: Invited professor, Nagoya University, Physics Department, Nagoya, Japan, 1987: ‘Chercheur-associé’ C.N.R.S, Laboratoire de Physique des Solides d’Orsay,

France1987: Chercheur associé CRSNG1985: Postdoctoral fellow NSERC


American Physical Society

Research keywords

Organic conductors and superconductors, collective states of matter, phase transitions, group of renormalisation

Name: François Boone Affiliation: Professor, Department of Electrical and Computer Engineering; Member, Centre de Recherche en Nanofabrication et en Nanocaractéri-sation (CRN2) and Centre d’Excellence en Génie de l’Information (CEGI), Université de SherbrookeDiploma: Ph.D., Electrical Engineering, 2000, École Polytechnique de Montréal, CanadaEmail: [email protected]: www.gel.usherbrooke.ca/lemo/

Name: Claude BourbonnaisAffiliations: Professor, Department of Physics, Université de Sherbrooke; Member of “Quantum materials” program, Canadian Institute for Ad-vanced Research (CIFAR)Diploma: Ph.D., Physics, 1985, Université de Sherbrooke, CanadaEmail: [email protected]: www.usherbrooke.ca/physique

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bOONe f. bOURbONNAIs C.

Research interests

We have developed a formalism to describe multiple collisions of low energy electrons. This model uses a diffusion matrix, which as an example can be generated by a R-matrix calculation, and corrects it for proximity effects. We have used this technique to investigate low energy electron scattering from DNA and are now applying it to crystalline ice and dimers of water molecules.


• “Diffraction in Resonant Electron Scattering from Helical Macromolecules: A and B type DNA”, L. G. Caron and L. Sanche, Phys. Rev. A 70, 032719 (2004).

• “Diffraction in resonant electron scattering from helical macromolecules: effects of the DNA backbone”, L. G. Caron and L. Sanche, Phys. Rev. A 72, 032726 (2005).

• “Low-energy electron collisions with tetrahydrofuran”, D. Bouchiha, J. D. Gorfinkiel, L. G. Caron and L. Sanche, Jour. Phys. B : At. Mol. Opt. Phys. 39, 975 (2006).

• “Temporary electron localization and scattering in disordered single strands of DNA”, L. Caron and L. Sanche, Phys. Rev. A 73, 062707 (2006).

• “Low-energy electron collisions with methanol”, D. Bouchiha, J. D. Gorfinkiel, L. G. Caron and L. Sanche, Jour. Phys. B: At. Mol. Opt. Phys. 20, 1259 (2007).

Research keywords

Electron diffusion, biological molecules, nucleotide bases, DNA, R matrix

Research interests

My research program aims at developing new strategies and techniques to fabricate superconductor-semiconductor hybrid devices to be used as sensors with extended sensitivity or flexibility.

To do so, the laboratory in place allows for nanofabrication of devices in oxide superconductors (junctions and SQUIDS) and other complex oxide materials (ferroelectrics, ferromagnetics, manganites, oxide multilayers, etc.)

Present work includes:

• The study of self switching diodes and transistors in Si, new types of devices which we fabricate, characterize (DC and RF) and simulate. Various applications are studied among which their use in semiconductor-on-superconductor hybrid device due to their ease of fabrication.

• The fabrication and study of engineered RF metamaterial both in conventional material and superconductors.

All this work therefore has a strong focus on using new materials for their unique properties in engineering applications (mainly in scientific instrumentation).


• “Electrical Characteristics and Simulation of Self-Switching-Diodes in SOI Technology”, G. Farhi, E. Saracco, J. Beerens, D. Morris, S.A. Charlebois and J.P. Raskin, Solid-State Electronics 51, 1245 (2007).

• “Terahertz emission properties of arsenic and oxygen ion-implanted GaAs based photoconductive pulsed sources”, B. Salem, D. Morris, Y. Salissou, V. Aimez, S. Charlebois, M. Chicoine and F. Schiettekatte, Journal of Vacuum Science & Technology A (Vacuum, Surfaces,

and Films) 24, 774 (2006).

• “Silent Phase Qubit Based on d-Wave Josephson Junctions”, M.H.S. Amin, A.Yu. Smirnov, A.M. Zagoskin, T. Lindström, S.A. Charlebois, T. Claeson and A.Ya. Tzalenchuk, Physical Review B 71, 064516 (2005).

• “Josephson dynamics of bicrystal d-wave YBa2Cu3O7-δ dc-SQUIDs”, T. Lindstrom, J. Johansson, T. Bauch, E. Stepantsov, F. Lombardi and S.A. Charlebois, Physical Review B 74, 014503 (2006).

• “Dynamical effects of an unconventional current-phase relation in YBCO dc SQUIDs”, T. Lindstrom, S.A. Charlebois, A.Ya. Tzalenchuk, Z. Ivanov, M.H.S. Amin and A.M. Zagoskin, Physical Review Letters 90, 117002 (2003).

Research keywords

Semiconductor devices, superconductor devices, high frequency, ferroelectric and ferromagnetic materials, metamaterials

Name: Laurent CaronAffiliation: Emeritus professor, Department of Physics, Université de SherbrookeDiploma: Ph.D., Solid-state Physics, 1968, MIT, USAEmail: [email protected]: www.physique.usherbrooke.ca/~caron

Name: Serge Charlebois Affiliation: Associate Professor, Department of Elec-trical and Computer Engineering; Member, Centre de Recherche en Nanofabrication et en Nanocarac-térisation (CRN2) and Centre d’Excellence en Génie de l’Information (CEGI), Université de Sherbrooke Diploma: Ph.D., Physics, 2002, Université de Sherbrooke, CanadaEmail: [email protected]: www.usherbrooke.ca/gelecinfo/ personnel/profs/charlebois.html

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CARON L. ChARLebOIs s.

Research interests

My research group focuses on the theoretical study of mesoscopic electron systems, that is micron to nanometer-sized electronic systems where quantum mechanical effects play a significant role. We are interested in understanding the complex interplay between disorder, inter-particle interactions and quantum effects in these systems, and in developing theoretical techniques to aid in the study of these systems. Where possible, we maintain a close connection to experiment, and collaborate with a number of experimental groups (both within Québec and internationally).

One strong theme in the group’s research has been the study of quantum measurement issues in mesoscopic electron systems. We have been interested in understanding how one can build detectors and amplifiers which operate as well as is allowed by the laws of quantum mechanics. Such an understanding is crucial if we ever wish to build devices which make practical use of the quantum coherence of mesoscopic systems (e.g. a quantum computer). We have also been active in building an understanding of mesoscopic systems containing a mechanical degree of freedom. Such nano-electromechanical systems are excellent test systems to explore the non-trivial quantum dissipative physics that arises when electronic degrees are strongly coupled to vibrational degrees of freedom. Such couplings are generically important in a variety of different nano-electronic devices.


• “Using a qubit to measure photon-number statistics of a driven thermal oscillator”, A. A. Clerk and D. Wahyu Utami, Phys. Rev. A 75, 042303 (2007).

• “Laser-like instabilities in quantum nano-electromechanical systems”, S. D. Bennett and A. A. Clerk, Phys. Rev. B. (Rapid Communcation) 74, 201301 (2006).

• “Cooling a nanomechanical resonator with quantum back-action”, A. Naik, O. Buu, M. D. LaHaye, A. D. Armour, A. A. Clerk, M. P. Blencowe and K. C. Schwab, Nature (London) 443, 193 (2006).

• “Back-action Noise in Strongly Interacting Systems: the dc SQUID and the Interacting Quantum Point-contact”, A. A. Clerk, Phys. Rev. Lett. 96, 056801 (2006).

• “Quantum Nano-electromechanics with Electrons, Quasiparticles and Cooper pairs: Effective Bath Descriptions and Strong Feedback Effects”, A. A. Clerk and S. Bennett New J. Phys. 7, 238 (2005)

Honors and awards

2007: Alfred P. Sloan Foundation Research Fellowship2005: Scholar, Canadian Institute for Advanced Research (CIFAR)2003: Canada Research Chair in Theoretical Mesoscopic Physics (Tier II)2001: Corson Fellowship, Cornell Center for Materials Research1997: Olin Fellowship, Cornell University1997: Clark Distinguished Teaching Award, Cornell University


Canadian Association of Physicists (CAP)American Physical Society (APS)

Research keywords

Mesoscopic physics, quantum noise, single-electron devices, nano-electromechanical systems

Research interests

My research has focused on the understanding of the magnetic state of various materials ranging from pure metals and alloys to semiconductors and insulating crystals. Analysis of measurements of magnetization and electronic transport phenomena has been the principal tool. Two current projects are:

Magnetic semiconductors, in particular dilute magnetic semiconductors, are under intense investigation at the present time as a medium for magnetic control of electronic information. Along with John Ström-Olsen and Mike Plischke at McGill in the early seventies, I published several seminal papers on Mn doped GeTe/SnTe detailing the formation of ferromagnetism via RKKY coupling through the free carriers. Currently, my PhD student Bucsa, with the aid of Sjoerd Roorda, is examining Mn-implanted InP in a search for an ordered magnetic state in this industrially important semiconductor.

On a second front, I maintain an ongoing collaboration with Art Yelon and David Ménard at École Polytechnique on the behaviour of networks of magnetic nanowires, notably ultrasoft amorphous, alloy wires formed through electrodeposition into alumina or polymer templates. Application in high-frequency devices provides one motivation of this research. Analysis of macroscopic magnetic properties, in particular the recently developed FORC technique, has led to a detailed understanding of both the array behaviour and the individual nanowire properties.


• “Statistical study of effective anisotropy field in ordered ferromagnetic nanowire arrays”, S. Zhao, L. Clime, K. Chan, F. Normandin, H. Roberge, A. Yelon, R.W.Cochrane and T. Veres, J. Nanoscience and Nanotechnology 7, 381 (2007).

• “First-order reversal curves diagrams of ferromagnetic soft nanowire arrays”, F. Béron, L. Clime, M. Ciureanu, D. Ménard, R.W. Cochrane and A. Yelon, IEEE Trans Mag. 42, 3060 (2006).

• “The role of non-collinear spins on the magnetic properties of uncoupled nanometer-size particles”, F. Zavaliche, F. Bensebaa, P. L’Ecuyer, T. Veres and R.W. Cochrane, J. Magn. Magn. Mater. 285, 204 (2005).

• “Ion-beam irradiation of Co/Cu nanostructures: Effects on giant magnetoresistance and magnetic properties”, M. Cai, T. Veres, F. Schiettekatte, S. Roorda and R.W. Cochrane, J. Appl. Phys. 95, 2006 (2004).

• “Structural evolution of Co/Cu nanostructures under 1 MeV ion-beam irradiation”, M. Cai, T. Veres, S. Roorda, F. Schiettekatte and R.W. Cochrane, J. Appl. Phys. 95, 1996 (2004).

Honors and awards

2007: Prix Reconnaissance Nano2007; NanoQuébec


Canadian Association of Physicists

Research keywords

Magnetism, magnetic materials, magnetometry, transport properties

Name: Aashish Clerk Affiliations: Assistant Professor, Department of Physics, McGill University; Canada Research Chair in Theoretical Mesoscopic Physics; Alfred P. Sloan Research Fellow, Alfred P. Sloan Foundation; Scholar, CIFAR Nanoelectronics Program; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Physics, 2001, Cornell University, NY, USAEmail: [email protected]: www.physics.mcgill.ca/~clerk/

Name: Robert CochraneAffiliation: Associate professor, Department of Physics, Université de MontréalDiploma: Ph.D., Physics, 1969, University of Toronto, CanadaEmail: [email protected]

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CLeRK A. COChRANe R.w.

Research interests

The Côté Research Group’s activities are in the simulation of material properties using ab initio methods such as density-functional theory. Our interests are in novel materials and in the design of new compounds with desirable properties. Because ab initio calculations can accurately describe the properties of materials, they are ideal tools for this task. It is therefore possible to investigate new structures, to predict their properties and to suggest possible modifications in order to tailor certain characteristics.

Our research interests range from semiconductors to organic materials. In the course of these investigations, we are studying materials such a C60 fullerenes, carbon nanotubes, organic polymers and GaAsN. Recently, we have proposed a new material that combines C60 and a metal-organic framework to tailor the elec-tronic properties to favor superconductivity and we are designing polymers with a low band gap which should improve the efficiency of organic photovoltaic devices.

Our research activities require us to continuously find ways to compute properties of materials and for the reason we are involved in the development of computational methods to better assess these characteristics. Our group is an active developer of the Abinit project, an open source code that implements state-of-the-arts methods in electronic structure calculations.


• “Experimental and theoretical studies of the E+ optical transition in GaAsN alloys”, V. Timoshevskii, M. Côté, G. Gilbert, R. Leonelli, S. Turcotte, J.-N. Beaudry, P. Desjardins, S. Larouche, L. Martinu, and R. A. Masut, Phys. Rev. B 74, 165120 (2006).

• “Fullerene in a metal-organic matrix: Design of the electronic structure”, S. Hamel, V. Timoshevskii, and M. Côté, Phys. Rev. Lett. 95, 146403 (2005).

• “Theory of Tunnel Ionization in Complex Systems”, T. Brabec, M. Côté, P. Boulanger and R. Lora, Phys. Rev. Lett. 95, 073001 (2005).

• “Structural relaxations in electronically excited poly(\emph{para}-phenylene)”, E. Artacho, M. Rohlfing, M. Côté, P. D. Haynes, R. J. Needs, and C. Molteni, Phys. Rev. Lett. 93, 116401 (2004).

• “Electronic, Structural, and Optical Properties of Conjugated Polymers Based on Carbazole, Fluorene, and Borafluorene”, J.-F. Brière and M. Côté, J. Phys. Chem. B 108, 3123 (2004).

Honors and awards

2002: Mérite honorifique, Cégep Sorel-Tracy2001: Programme stratégique de professeurs-chercheurs (FQRNT)1995: Outstanding Graduate Student Instructor Award, UC Berkeley1993: NSERC Centennal Scholarship 19671993: Science College Medal, Université Concordia1993: The Harry & Grace Colle Scholarships, Université Concordia1992: Upreti Award and Medal, Université Concordia


Canadian Association of PhysicistsAmerican Physics SocietyAmerican Association for the Advancement of Science

Research keywords

Electronic structure, ab initio calculations, organic electronic, superconductivity, semiconductors

Research interests

When a gas of electrons is confined, at very low temperature, into the lowest-energy state of a quantum well, it behaves as is it was effectively two-dimensional. This reduction in dimensionality increases the role of the coulombian interaction between electrons. When a strong magnetic field, perpendicular to the plane of the two-dimensional electron gas (2DEG) is added to the system, the energy of the electrons is further quantized into Landau levels. As the electrons fill these levels, a rich diversity of electronic states are observed experimentally. The most illustrious of these states are the Laughlin liquid states occurring at integer and some fractional fillings of the Landau levels where the electrons collectively ensemble themselves to produce an exact quantization of the Hall conductance. In my research group, we study other collective states of the 2DEG that occur away from the integer filling of the Landau levels: Wigner crystal, Skyrmion crystal, stripe and bubble phases. We also look at similar states that occur in the 2DEG formed in a double quantum well structure and in single layers of graphite. We study the energetics of these states as well as their collective excitations and experimental signature. We try to understand how the quantum confinement, coulombian interactions and quantum fluctuations conspire to give to these states their unique transport and electronic properties.


• “Quantum depinning transition of quantum Hall stripes”, M.-R. Li, H. A. Fertig, R. Côté and Hangmo Yi, Phys. Rev. Lett. 92, 186804 (2004).

• “Pseudospin vortex-antivortex states with interwoven spin textures in double-layer quantum Hall systems”, H.A. Fertig, K. Mullen, J. Bourassa, B. Roostaei and R. Côté, Phys. Rev. B 74, 195230 (2006).

• “Collective excitations, fluctuations and phase transitions in Skyrme crystal”, R. Côté, A.H. MacDonald, L. Brey, H.A. Fertig, S.M. Girvin and H.T.C. Stooff, Phys. Rev. Lett. 78, 4825 (1997).

• “Solitonic excitations in linearly coherent channels of bilayer quantum Hall stripes”, C. B. Doiron, R. Côté and H. A. Fertig, Phys. Rev. B 72, 115336 (2005).

• “Skyrme crystal in a two-dimensional electron gas”, L. Brey, H.A. Fertig, R. Côté and A.H. MacDonald, Phys. Rev. Lett. 75, 2562 (1995).


Canadian association of physicistsAmerican Physics Society

Research keywords

Bidimensionnal electron gas, quantum microstructures, quantum Hall effect, Wigner crystal, skyrmions, graphene

Name: Michel CôtéAffiliations: Professor, Department of Physics, Université de Montréal; Site Director of the Réseau québécois de calcul de haute performance (RQCHP); Member of the Advisory Board of the Abinit Project; Adjunct Fellow du Collège des Sciences, Université ConcordiaDiploma: Ph.D., Physics, 1998, University of California at Berkeley, USAEmail: [email protected]: www.phys.umontreal.ca/~michel_cote

Name: René CôtéAffiliations: Professor and Director of Graduate Studies in physics, Department of Physics, Université de Sherbrooke Diploma: Ph.D., Physics, 1988, University of Toronto, CanadaEmail: [email protected]: www.physique.usherbrooke.ca/~rcote/

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CôTé M. CôTé R.

Research interests

Our research group focuses on the development of an atomic-level understanding of thin film growth and interfacial reactions in materials targeted for advanced ap-plications in the fields of microelectronics and optoelectronics. We are particularly interested in thin film synthesis and modification processes that operate under highly kinetically-constrained conditions. This enables us to fabricate metastable materials and structures with unique tailorable properties which can then be used to investigate new physical phenomena that arise at the nanoscale.

A large fraction of our research effort focuses on the design and the synthesis of materials that exhibit reduced dimensionality (2, 1, and 0) characteristics. In this area, we develop highly-strained III-V heterostructures for band gap engineering of micro- and optoelectronic devices. We also investigate the three-dimensional self-organization of self-assembled quantum dot arrays as well as band gap tuning processes based on stimulated intermixing techniques.

In collaboration with IBM Research, we are investigating interfacial reactions and phase transitions in a variety of materials systems for which dimensions are of the order of several nanometers. Using an array of in situ probes, we study the influence of dimensions, nanostructure, and texture on the kinetics of phase transformations.

Finally, our group also contributes to collaborative projects aimed at developing novel hybrid organic/inorganic electronic and optoelectronic devices.


• “Drastic ion-implantation-induced intermixing during annealing of self-assembled InAs/InP(001) quantum dots”, C. Dion, P. Desjardins, S. Raymond, P.J. Poole, F. Schiettekatte and M. Chicoine, Nanotechnol. 18, 015404 (2007).

• “Nitrogen incorporation and lattice constant of strained dilute GaAsN layers on GaAs (001): An ab initio study”, N. Shtinkov, P. Desjardins, R.A. Masut and M. Côté, Phys. Rev. B 74, 35211 (2006).

• “Carbon nanotube sheets as electrodes in organic light emitting diodes”, C.M. Aguirre, S. Auvray, S. Pigeon, R. Izquierdo, P. Desjardins and R. Martel, Appl. Phys. Lett. 88, 183104 (2006).

• “Reaction of thin Ni films with Ge: Phase formation and texture”, S. Gaudet, C. Detavernier, C. Lavoie and P. Desjardins, J. Appl. Phys. 100, 34306 (2006).

• “Dynamics of ion bombardment-induced modifications of Si (001) at the radio-frequency-biased electrode in low-pressure oxygen plasmas: In Situ spectroscopic ellipsometry and Monte-Carlo study”, A. Amassian, M. Svec, P. Desjardins and L. Martinu, J. Appl. Phys. 100, 063526 (2006).

Honors and awards

2000: Canada Research Chair in Advanced Materials for Microelectronics and Optoelectronics (Tier II)


Ordre des ingénieurs du QuébecAmerican Vacuum Society (AVS)Materials Research Society (MRS)Microscopy Society of America

Research keywords

Thin film physics, surface and interface physics, microstructural and microchemi-cal characterization, materials for electronics and optoelectronics

Research interests

The first area relates to the fabrication of devices and sensors with semiconduc-tor by innovative techniques of electrons/ions beam nanolithography. The devices currently developed are based on materials including among others silicon nano-crystals and quantum dots. These devices include for example single electron transistors, high sensitivity photodetectors and single electron memories.

The second area of research activities is mainly focused on the analysis of semiconductors devices and nanostructures by advanced scanning electron microscopy techniques. These techniques call mainly upon the use of scanning electron microscope for voltage contrast imaging, X-ray microanalysis (EDX), cathodoluminescence (CL), electron beam induced current (EBIC) and using variable pressure microscopes, charge contrast imaging. The structures currently being studied include in particular quantum dots (InAs/InP and InAs/GaAs) and GaN based devices. Electron microscope modeling techniques are also studied in order to develop tools for characterization for metrologies application in the semiconductor industry.



• “CASINO V2.42-A Fast and Easy-to-use Modeling Tool for Scanning Electron Microscopy and Microanalysis Users”, D. Drouin, A.R. Couture, D. Joly, X. Tastet, V. Aimez and R. Gauvin, Scanning, 29, 92 (2007).

• “A damascene process to be used as a building block for nanoscale devices”, C. Dubuc, J. Beauvais and D. Drouin, IEEE Tran Nano, (Submitted).

• “Carrier recombination near threading dislocations in GaN epilayers by low voltage cathodoluminescence”, N. Pauc, M. R. Phillips, V. Aimez and D. Drouin, Appl. Phys. Lett. 89, 161905 (2006).

• “Carrier diffusion processes near threading dislocations in GaN and GaN:Si characterized by low voltage cathodoluminescence”, N. Pauc, M. R. Phillips, V. Aimez and D. Drouin, Superlattices and Microstructures 40, 557 (2006).

Honors and awards

1997: Médailles du mérite des gouverneurs de la Faculté, Université de Sherbrooke

1995 to 1997: MAS Distinguished Student Award at Microscopy and Micro analysis ’97, ’96, ’951996: Castaing Award for Best Student Paper at Microscopy and Microanalysis ’961996: Bourse mérite de l’Université de Sherbrooke1993 to 1996: American Society for Metals Student Award1994: Best Student Poster Award at Scanning 941994: Bourse d’excellence de l’Ordre des Ingénieurs du Québec


Ordre des Ingénieurs du QuébecMicrobeam Analysis SocietyMicroscopy Society of Canada

Research keywords

Cathodoluminescence, electron beam lithography, single electron transistor, quantum dots devices, scanning electron microscopy

Name: Patrick Desjardins Affiliations: Professor, Dept. of Physical Engineering, École Polytechnique de Montréal; Canada Research Chair in Advanced Materials for Micro elec tronics and Optoelectronics; President, Scientific Affairs Committee, NanoQuébec; Associate Editor, Thin Solid Films Diploma: Ph.D., Engineering physics, 1996, École Polytechnique de Montréal, Canada Email: [email protected] Web: http://desjardins.phys.polymtl.ca

Name: Dominique Drouin Affiliations: Professor, Department of Electrical and Computer Engineering; Member, Centre de Recherche sur la Nanofabrication et Nanocaracteri-sation (CRN2); and Co-Director, Centre d’excellence en génie de l’information (CEGI), Université de Sherbrooke Diploma: Ph.D., Mechanical engineering, 1998, Université de Sherbrooke, CanadaEmail: [email protected]: www.gel.usherbrooke.ca/crn2/pages_ personnel/drouin/accueil.htm

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DesjARDINs P. DROUIN D.

Research interests

My research centers on the physics and formation of paper and on printing processes, with special focus on the development of new fiber functionalities and nanotechnologies.

Paper formation is explored with numerical simulations of fiber flow and deposi-tion coupled to experimental results from X-ray tomography (which measures the three-dimensional structure of paper at a scale of 0.7 µm). Cellulose fibers, the basic building block of paper, can also be modified, either by addition of polymer or directly by grafting of various functional groups. Those two aspects are crucially linked to the improvement of existing paper and to the development of new “intelligent” papers.

The penetration and flow of a fluid (water or ink) inside the paper porous structure has important industrial applications whether it is in papermaking (forming, pressing and drying phases) or in the field of printing (conventional offset printing or digital ink jet printing). The challenge in this case is to link the large scale properties of the flow with the smallest scales of the paper structure (about 10 nm in coated paper) and the time scales relevant to industrial processes (only a few milliseconds).


• “Fluctuations in fluid invasion into disordered media”, M. Rost, L. Laurson, M. Dubé and M.J. Alava, Phys. Rev. Lett. 98, 054502 (2007).

• “Front Roughening in Three-Dimensional Imbibition”, M. Dubé, C. Daneault, V. Vuorinen, M. Alava and M. Rost, Eur. Phys. J. B 56, 15-26 (2007).

• “Effect of Paper Properties on Print Quality”, M. Péralba, M. Dubé, L. Cormier and P.J. Mangin, 59th Technical Association of the Graphic Arts Conference,

Pittsburgh (2007).

• “Front Instability in Drying of Paper Coating”, M. Dubé and C. Daneault, Nordic Pulp Pap. Res. J. 21, 676 (2006).

• “Hydrodynamics of Ink Transfer”, M. Dubé, F. Drolet, C. Daneault and P.J. Mangin, Tappi publications, International Printing and Graphic Arts Conference

(2006).

Honors and awards

2005: John S. Bates award, Pulp and Paper Technical Association of Canada


Pulp and Paper Technical Association of Canada,Secretary, Printing and Graphic Arts committee of PAPTAC

Research keywords

Disordered structure, microfluidics, coatings, printing, surfaces

Research interests

The Dubowski Research Group carries out both fundamental and applied research concerning interfacing of organic and biological materials with semiconductors. Our interest is primarily driven by the need to stabilize electric and optical properties of semiconductor nanostructures making their way into commercial nanophotonic and microelectronic devices. We are also interested in inorganic-organic interfaces that can be used to modulate optical signals originating from quantum semiconductors and which would allow for the carrying out of rapid monitoring of the immobilization of minuscule amounts of biological matter, such as viruses or bacteria. Formation of such interfaces requires attaching special ‘bio-linkers’ to semiconductor surfaces, which is a relatively poorly known process. We carry out theoretical calculations aiming to model and describe some of the basic processes leading to the formation of self-assembled monolayers (SAM) of alkanethiols on semiconductor surfaces. This offers an attractive path towards developing a suitable bio-linker technology.

Another area of our interest concerns the development of laser-based methods for selective area tuning of the emission wavelength of quantum well and quantum dot wafers. This activity has been driven by the lack of precision offered by the state-of-the-art technologies of thin film epitaxy required for the successful introduction of innovative nanodevice ideas to the nanotechnology market.


• “Structure, bonding nature and binding energy of alkanethiolate on As-rich GaAs (001) surface: a density functional theory study”, O. Voznyy and J.J. Dubowski, J. Phys. Chem. B 110, 23619 (2006).

• “Aging and detergent washing effects of the surface of (001) and (110) GaAs passivated with hexadecanethiol”, K. Moumanis, X. Ding, J.J. Dubowski and E. Frost, J. Appl. Phys. 100, 034702 (2006).

• “Immobilization of avidin on (001) GaAs”, X. Ding, K. Moumanis, J.J. Dubowski, E. Frost and E. Escher, Appl. Phys. A 83, 357 (2006).

• “FTIR and photoluminescence spectroscopy of self-assembled monolayers of long-chain thiols on (001) GaAs”, X. Ding, K. Moumanis, J.J. Dubowski, L. Tay and N.L. Rowell, J. Appl. Phys. 99, 54701 (2006).

• “Multibandgap quantum well wafers by IR laser quantum well intermixing: simulation of the lateral resolution of the process”, O. Voznyy, R. Stanowski and J.J. Dubowski, J. Laser Micro/Nanoengineering, 1, 48 (2006).

Honors and awards

2003: Canada Research Chair in Quantum Semiconductors (Tier I)1998: Fellow of SPIE – The International Society for Optical Engineering, USA1997: Visiting Professor at Osaka University; Osaka, Japan1982: National Research Council Canada Post-Doc Fellowship; Ottawa, Canada 1979: The Minister of Higher Education Award; Technical University of Wroclaw,

Poland


Canadian Association of Physicists (CAP)American Physics Society (APS)

Research keywords

Semiconductors, surface and interfaces, laser-mater interaction, nanophotonics, biosensors

Name: Martin Dubé Affiliation: Researcher, Centre Intégré en Pâtes et Papiers (CIPP), Université du Québec à Trois-RivièresDiploma: Ph.D., Physics, 1997, University of British-Columbia, CanadaEmail: [email protected]: www.uqtr.ca/~dubma

Name: Jan J. Dubowski Affiliations: Professor, Dept. of Electrical and Computer Engineering; and Member, Centre d’excellence en génie de l’information (CEGI) and Centre de Recherche en Nanofabrication et en Nano-carac térisation (CRN2), Université de Sherbrooke; Canada Research Chair in Quantum Semiconductors; Member, Ré-seau québécois de calcul de haute performance (RQCHP); Member, Plasma Québec Diploma: Ph.D., Semiconduc tor Physics, 1978, Wroclaw University of Technology, Poland Email: [email protected] Web: www.gel.usherbrooke.ca/crn2/pages_ personnel/dubowski/accueil_en.htm

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DUbe M. DUbOwsKI j.j.

Research interests

Professor Fournier’s research group studies the physical behaviors of thin films and components containing oxides of the perovskite type. These layers are synthesized by the technique of ablation, using a pulsed laser excimer, and they are studied under extreme conditions such as low temperatures (340mK to 400K) and either very weak (< 1 mOe) or intense (up to 16T) magnetic fields.

Extraordinary properties generally arise as a consequence of the strong electron correlations in the volumes or at the interfaces of these materials. These include high Tc superconductors, ferromagnetic manganites with colossal magnetoresistance, multiferroic structures including double-perovskites of the A2BB’O6 type… Several components with potential technological applications or possibly leading to the generation of new states of the matter are also studied: Josephson junctions, SQUIDs and superconductor monolayers-based terahertz emitting antennas, oxides multi-layer combining various order parameters such as superconductivity, ferromagnetism and ferroelectricity, spin injection structures, multiphase epitaxial layers… These materials and the new artificial structures arising from them will contribute to the next generation of electronic components, in particular for applications in the fields of telecommunications, detection, data processing and medicine.


• “Magnetodielectric effect in double perovskite La2CoMnO6 thin films”, M.P. Singh, K.D. Truong and P. Fournier, Appl. Phys. Lett. 91, 042504 (2007).

• “Evidence of bi-domain structure in double perovskite La2CoMnO6 thin films”, M.P. Singh, S. Charpentier, K.D. Truong and P. Fournier, Appl. Phys. Lett. 90, 211915 (2007).

• “Different roles of cerium substitution and oxygen reduction in transport in Pr2-xCexCuO4-δ thin films”, J. Gauthier, S. Gagné, J. Renaud, M.-È. Gosselin, P. Richard and P. Fournier, Phys. Rev. B 75, 024424 (2007).

• “Optical determination of the superconducting energy gap in electron-doped Pr1.85Ce0.15CuO4”, C. C. Homes, R. P. S. M. Lobo, P. Fournier, A. Zimmers and R. L. Greene, Phys. Rev. B 74, 214515 (2006).

• “Observation of charge-ordering by Raman scattering in Nd0.5Ca0.5MnO3 thin films”, S. Charpentier, M. Gill-Comeau, S. Jandl and P. Fournier, J. Phys.: Condens. Matter. 18, 7193 (2006).

Honors and awards

2000: One-year teaching relief, Canadian Institute for advanced Research (CIFAR) 1994: NSERC Post-doctoral scholarship; Stanford University


Canadian Association of Physicists (CAP)American Physical Society (APS)Materials Research Society (MRSAssociation canadienne-française pour l’avancement des sciences (ACFAS)

Research keywords

Thin films, superconductivity, magnetism, multiferroics, multilayers

Research interests

We are using optical spectroscopy and the fundamental aspects of light-matter interactions to study the properties of novel materials, to understand the effects of multidimensional confinement, and to tailor the properties of quantum struc-tures to suit particular needs. We specialize in the techniques of luminescence, luminescence excitation, modulated reflection, and Raman scattering, performed under external perturbations to achieve a better understanding of the system under study. These external perturbations include a low-temperature environment, ultrafast pomp-probe, strong electric or magnetic fields, and high-pressure in a diamond anvil cell. In recent years, we have been performing these spectros-copy techniques at a very high spatial resolution to isolate and study a single nanostructure at a time.

Recently, we have been particularly interested in atomic-size quantum dots com-posed of a few isovalent impurities. This type of nanostructure is well adapted for demonstrating, for example, a gate-controlled single-electron memory or a source of entangled photons on demand. The objectives of this program are: to advance the understanding of the physics governing the behavior of atomic-scale quantum dots, to explore their advantages with respect to larger quantum structures, and, anticipating long-term needs for ever larger integration, aims at developing new approaches for the creation of atomic-size devices.


• “Giant spin-orbit bowing in GaAsBi”, B. Fluegel, S. Francoeur, A. Mascarenhas, S. Tixier, E. Young and T. Tiedje, Phys. Rev. Lett. 97, 067205 (2006).

• “Physics of Isoelectronic dopants in GaAs”, A. Mascarenhas, S. Francoeur and S. Yoon, Chapter 6, pages 179–221, Elsevier (2005).

• “Optical spectroscopy of single impurity centers in semiconductors”, S. Francoeur, J. Klem, and A. Mascarenhas, Phys. Rev. Lett. 93, 067403 (2004).

• “Origin of the nitrogen-induced optical transitions in GaAs1-xNx”, S. Francoeur, M.-J. Seong, M. Hanna, J. Geisz and A. Mascarenhas, Phys. Rev. B 68, 075207 (2003).

• “Two-dimensional array of self-assembled AlInAs quantum wires”, S. Francoeur, A. Norman, A. Mascarenhas, E. Jones, J. Reno, S. Lee and D. Follstaedt, Appl. Phys. Lett. 81, 529 (2002).



Research keywords

Nanoscience, optical spectroscopy, atomic electronics, nanostructures

Name: Patrick FournierAffilations: Professor, Department of Physics, Université de Sherbrooke Fellow, Quantum Materials Program of the Canadian Institute for Advanced Research (CIFAR); Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Physics, 1993, Université de Sherbrooke, CanadaEmail: [email protected]: www.physique.usherbrooke.ca/fournier

Name: Sébastien FrancoeurAffiliations: Professor, Department of Physical Engineering, École Polytechnique de MontréalDiploma: Ph.D., Electric engineering and Physics, 2004, University of Colorado at Boulder, USAEmail: [email protected]

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fOURNIeR P. fRANCOeUR s.

Research interests

In recent years, the electronic properties of low-dimensional structures such as electrons “trapped” in quantum wells (2D) or flowing in a quantum wire (1D) have drawn a high-level of interest for both fundamental aspects and promising device applications. As the temperature of the electrons present in these structures approaches zero, totally new properties emerge from a competition between electron-electron interactions, disorder, and fluctuations. Examples include “bizarre” phenomenas such as fractional quantum statistics in 2D, as well as the separation of spin and charges in 1D.

Material-wise, we use GaAs/AlGaAs grown in the highest-moblity Molecular Beam Epitaxy (MBE) facility in the world (Lucent), as well as the cleanest material in nature, 3He near T=0. We carry out measurements down to ~8 mK, up to 16T. In our lab, we develop and implement novel tool such as resistively detected NMR with “too few spins”, scanned probe microscopy, as well as new optical tech-niques. Starting from raw semiconducting material, we tailor-fabricate structures for electrons, or nanoholes for quantum fluids using clean room fabrication pro-cesses evolved from the nanotech community. In Gervais’ lab, the search for new quantum phases of matter occurs when the nanotech tools and low-temperature know-how connect with quantum physics.


• “Local Control of Light Polarization with Low-temperature Fiber Optics”, A. H. Mack, J. Riordon, C.R. Dean, R. Talbot and G. Gervais, Optics Letters 32, 1378 (2007). (also in the Virtual Journal of Quantum

Information, June 2007).

• “Evidence for Skyrmion Crystallization from NMR Relaxation Experiments”, G. Gervais, H.L. Stormer, D.C. Tsui, W.G. Moulton, P.L. Kuhns, A.P. Reyes, K.W. Baldwin, K.W. West and L.N. Pfeiffer, Phys. Rev. Lett. 94, 196803 (2005). (also in the Virtual Journal of

Nanoscale Science & Technology, May 30, 2005).

• “Competition between Fractional Quantum Hall Liquid, Bubble and Wigner Crystal Phases in the Third Landau Level”, G. Gervais, L.W. Engel, K.W. Baldwin, K.W. West, L.N. Pfeiffer, H.L. Stormer and D.C. Tsui, Phys. Rev. Lett. 93, 266804 (2004). (also in the Virtual Journal of

Nanoscale Science & Technology, January 10, 2005).

• “A1 and A2 Transitions in Superfluid 3He in 98% Porosity Aerogel”, H.C. Choi, A.J. Gray, C.L. Vicente, J.S. Xia, G. Gervais, W.P. Halperin, N. Mulders and Y. Lee, Phys. Rev. Lett. 93, 145302 (2004).

• “Specific Heat of Disordered Superfluid 3He”, H. Choi, K. Yawata, T.M. Haard, J.P. Davis, G. Gervais, N. Mulders, P. Sharma, J.A. Sauls and W. P. Halperin, Phys. Rev. Lett. 93, 145301 (2004).

Honors and awards

2005: Alfred P. Sloan Fellow2005: Cross-appointed, Canadian Institute for Advances Research –

CIFAR Nanoelectronics program 2004: Scholar, Canadian Institute for Advances Research – CIFAR Quantum

materials program


Canadian Association of Physicists (CAP)American Physical Society (APS)Association francophone pour le savoir (ACFAS)

Research keywords

Nanoscience, semiconductor quantum wells, nanoelectronics, nanofluidics, quantum information

Research interests

My interests are in understanding and predicting the properties of nonequilibrium and metastable structures. As a specific example, the structural and mechanical properties of materials, e.g, how brittle they are, and how they self-assemble, are determined by a nonequilibrium processing history, giving rise to a complex structure on the scale of nanometers to microns. Applications make use of this complex structure by dynamically tuning the morphology to, for example, minimize failure rates of materials under stress. What is left is not an equilibrium phase, it is a nonequilibrium material with a tuned microstructure. Often these complex structures involve scale invariance in an intrinsic and deep way, where a dominant length scale asymptotically controls the evolution of the structure on all scales. Hence, a fundamental issue in physics is involved: where do such complex structures come from, and how can they be understood? With my group, I am investigating these and other systems by nonlinear analysis, and large-scale computer simulation. We make use of ideas and analogies developed in other contexts, particularly those developed in the theory of phase transitions, to under-stand the origin of complex structures.


• “Phase-field crystal modeling and classical density functional theory of freezing”, K. R. Elder, N. Provatas, J. Berry, P. Stefanovic and M. Grant, Phys. Rev. B 75, 064107 (2007).

• “Dissipative phenomena and acoustic phonons in isothermal crystals: A density-functional theory study”. S. Majaniemi and M. Grant, Phys. Rev. B 75, 054301 (2007).

• “Rupture of an extended object: A many-body Kramers calculation”, A. Sain, C. L. Dias and M. Grant, Phys. Rev. E 74, 046111 (2006).

• “Designable structures are easy to unfold”, C. L. Dias and M. Grant, Phys. Rev. E 74, 042902 (2006).

• “Diffusive Atomistic Dynamics of Edge Dislocations in Two Dimensions”, J. Berry, K. R. Elder and M. Grant, Phys. Rev. E 73, 031609 (2006).

Honors and awards

2004: Fellow Royal Society of Canada2002: James McGill Chair; McGill University1998: Rutherford Memorial Medal in Physics, Royal Society of Canada



Research keywords

Nonequilibrium statistical mechanics, phase transitions, crystal growth, open systems, complex fluids

Name: Guillaume GervaisAffiliations: Assistant Professor, Department of Physics, McGill University; Scholar, CIFAR Nanoelectronics and Quantum Materials Program; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ) Diploma: Ph.D., Physics, 2002, Northwestern University, USAEmail: [email protected]: www.physics.mcgill.ca/~hedbergj/ labpage/home.htm

Name: Martin GrantAffiliations: Professor, Department of Physics; Dean, Faculty of Science; James McGill professor, McGill UniversityDiploma: Ph.D., Physics, 1982, University of Toronto, CanadaEmail: [email protected]: www.physics.mcgill.ca/~grant/

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GeRVAIs G. GRANT M.

Research interests

The Grütter Research Group develops and builds instrumentation, mainly atomic force microscopy based, and applies them to fundamental problems in information technology and biology.

We push the limits of instrumentation, building and operating devices where we can image, manipulate and characterize every single atom and in some cases even directly detect and image single electrons and photons. The aim of this research is to under-stand the fundamental structure-function relationship of nanoscale devices: how does the atomic structure of the system relate to properties relevant for IT applications. In collaboration with theoreticians, Grütter applies these tools, techniques and materials to provide experimental data that will allow the stringent testing of modeling and theoreti-cal concepts.

In biological applications, we probe the visocelastic properties of living neurons and smooth muscle cells. The aim of this is to understand how molecular structures affect mechanical properties and information processing at the cellular level. By collaborating with researchers in the life sciences we probe deeper into how neurons form junctions or how small molecules can lead to asthmatic attacks by contraction of smooth muscle cells. By understanding structure-function in such biological systems, we might be able to create new nanoelectronic and nanomechanical systems with superior properties.


• “Dendritic Spine Viscoelasticity and Soft-Glassy Nature: Balancing Dynamic Remodeling with Structural Stability”, B.A. Smith, H. Roy, P. De Koninck, P. Grütter and Y. De Koninck,

Biophys. J. 92, 1419 (2007).

• “Nanopits as Templates for Building a Molecular Device”, J. Mativetsky, S. A. Burke, S. Fostner and P. Grütter,

Small 3, 818 (2007).

• “Templated Growth of 3,4,9,10-Perylenetetracarboxylic Dianhydride Molecules on a Nanostructured Insulator”, J. Mativetsky, S. A. Burke, S. Fostner and P. Grütter,

Nanotechnology 18, 105303 (2007).

• “A differential microcantilever-based system for measuring surface stress changes induced by electrochemical reactions”, V. Tabard-Cossa, M. Godin, L.Y. Beaulieu and P. Grütter,

Sensors and Actuators B-Chemical 119, 352 (2006).

• “Plasticity, healing and shakedown in sharp-asperity nanoindentation”, G.L.W. Cross, A. Schirmeisen, P. Grütter and U.T. Durig,

Nature Materials 5, 370 (2006).

Honors and awards

2006: James McGill Chair, McGill University2005: Carrie Derick Award for Excellence in Graduate Supervision and Teaching,

McGill University2005: Rutherford Memorial Medal in Physics, Royal Society of Canada2002: Canadian Institute for Advances Research – CIAR Young Explorer Prize2000: McGill William Dawson Scholar, McGill University2001: Steacie Fellowship; Natural Sciences and Engineering Research Council of

Canada (NSERC)1991: Treubel Fonds Habilitations Stipendium, University of Basel1991: Swiss National Science Foundation Post-Doc Fellowship, University of Basel1989: IBM World Trade Fellowship, IBM


Canadian Association of PhysicistsAmerican Physics SocietySchweizerische Physikalische GesellschaftDeutsche Physikalische Gesellschaft

Research keywords

Nanoscience, scanning probe microscopy, nanoelectronics, biophysics, sensors

Research interests

Our research interests focus on the development of new BioMEMS (Bio- Microelectromechanical Systems) aimed for biomedical applications, in particular functionalised microwells for cell culture.

The unifying thread in our research program will be the design, characterization and development of new cell-culture platforms for the detection of cell responses to controlled culture conditions. Its originality primarily lies in the integration on a single platform of microfluidics components and of arrays of electrochemical and optical microsensors. In particular, arrays of ion-selective microelectrodes for real-time intra- or extracellular detection of cell responses will be combined with different types of drug delivery systems. These platforms have the potential to satisfy a broad range of applications varying from diagnostic, tissue-engineered products, to cell-based drug screening tools to basic molecular biology tools.


• “Development of an array of ion-selective microelectrodes aimed for the monitoring of extracellular ionic activities”, O.T. Guenat, S. Generelli S, N.F. de Rooij, M. Koudelka-Hep, F. Berthiaume and M. Yarmush, Anal. Chem. 78, 7453 (2006).

• “Generic technological platform for microfabricating silicon nitride micro- and nanopipettes arrays”, O.T. Guenat, S. Generelli, M. Dadras, L. Berdondini, N.F. de Rooij and M. Koudelka-Hep, Journal of Micromechanics and Microengineering 15, 2372 (2005).

• “Partial electroosmotic pumping in complex capillary systems, Part 2: Fabrica-tion and application of a micro total analysis system suited for volumetric nanotitrations”, O.T. Guenat, D. Ghiglione, W.E. Morf and N.F. de Rooij, Sensors and Actuators B 72, 273 (2001).

• “Partial electroosmotic pumping in complex capillary systems, Part 1: Principles and general theoretical approach”, W.E. Morf, O.T. Guenat and N.F. de Rooij, Sensors and Actuators B 72, 266 (2001).

• “Triangle-programmed coulometric nanotitrations completed by continuous flow with potentiometric detection”, O.T. Guenat, W.E. Morf, B.H. van der Schoot and N.F. de Rooij, Anal. Chem. 72, 1585 (2000).

Honors and awards

2005: Swiss National Science Foundation, Advanced researcher grant, Harvard Medical School


IEEE Engineering in Medicine and Biology Society (EMBS) member

Research keywords

Microsystems for biomedical applications (BioMEMS), microfluidics, electrochemical micro- and nanosensors, microwells for cell culture

Name: Peter Grütter Affiliations: Professor, Dept. of Physics; James McGill professor; Associate Dean of Research and Graduate Studies, Faculty of Science; Director of Graduate Studies in Physics; and Associate Member, Dept. of Chemistry, McGill University; Fellow and Scientific Director, CIFAR Nanoelectronics Program; Scientific Director, NSERC Nano Innovation Platform; Director, RQMP; Associate Member, CRCN (Centre de recherche sur le cerveau, le comportement et la neuropsychiatrie), Université Laval Diploma: Ph.D., Physics, 1989, University of Basel, Switzerland Email: [email protected] Web: www.physics.mcgill.ca/spm/

Name: Olivier Guenat Affiliations: Assistant Professor, Dept. of Engineering Physics; and Member of the Biomedical Science and Technologies Research Group (GRSTB), École Poly-technique de Montréal; Member of the Biomedical Engineering Department, University of Montréal – École Polytechnique de Montréal Diploma: Ph.D., Micro-and nanotechnology, 2000, University of Neuchâtel, SwitzerlandEmail: [email protected]: www.polymtl.ca/recherche/rc/en/professeurs/ details.php?NoProf=343

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GRüTTeR P. GUeNAT O.

Research interests

More than 30 years ago, a pioneering technique, known as Electric Recoil Detection (ERD) to profile light elements in high mass substrate, was originated in our lab (J. Appl. Phys. 47 (1976). Since 1982, I am involved as an initiator and one of the first investigators to modify this ERD technique by incorporating a Time-of- Flight (TOF) system to make it more versatile and quantitatively reliable depth-profiling tool in thin film research. Several elements including hydrogen, in uniformly coated thin films of thickness ranging a few tens of nm to a few hundreds of nm, are simultaneously profiled in a singled experiment. Since past several years I have been working as a leader of the ERD group by maintaining, upgrading, and providing this facility to the researchers in thin film technology. It is to be noted that our ERD-TOF facility is unique in Canada and is serving a large thin film research community and playing a remarkable role in many of their research projects. Sometimes I am also involved as a collaborator in some of these projects.

From time to time I am also involved in developing and applying other energetic Ion Beam Analysis Techniques such as Rutherford Backscattering Spectrometry (RBS), Nuclear Reaction Analysis (NRA).


• “Characterization of Silicon Carbide Thin Films Obtained Via Sublimation of a Solid Polymer Source Using Polymer-Source CVD Process”, E.H. Oulachgar, C. Aktik, S. Dostie, S. Gujrathi and M. Scarlete, MRS Spring Meeting, in Symposium A: Amorphous and Polycrystalline

Thin-Film Silicon Science and Technology (Abs. A5.5) April 9-13, 2007.

• “Cross section for 14N(α, p0)17O reaction in the energy range 3.2 - 4.0 MeV”, P. Wei, S.C. Gujrathi, M. Guihard and F. Schiettekatte, Nucl. Instr. And Meth. B 249, 85 (2006).

• “Alleria: a new interface to the ERD program”, F. Schiettekatte, M. Chicoine, S. Gujrathi, P. Wei and K. Oxorn, Nucl. Instr. and Meth. B 219-220, 125 (2004).

• “Round Robin: measurement of H implantation distributions in Si by elastic recoil detection”, G. Boudreau, R.G. Elliman, R. Grötzschel, S.C. Gujrathi, C. Jeynes, W.N. Lennard, E. Rauhala, T. Sajavaara, H. Timmers, Y.Q. Wang and T.D.M. Weijers, Nucl. Instr. and Meth. B 222, 547 (2004).

• “Quantitative compositional depth profiling of SixGe1-x-yCy thin films by simultaneous elastic recoil detection and Rutherford backscattering spectrometry”, S.C. Gujrathi, S. Roorda, J.D. D’Arcy, R.J. Pflueger, P. Desjardins, I. Petrov and J.E. Greene, Nucl. Instr. and Meth. in Research B 136-138, 654 (1998).

Research keywords

Ion beam analysis (ERD, RBS, NRA), energetic ion-solid interactions, thin films, multilayer coatings

Research interests

My current research interest is in theoretical calculations of structural, electronic and quantum transport properties of nanoelectronic device systems. I am also interested in computational physics. Our main theoretical tool includes Keldysh nonequilibrium Green’s function (NEGF) and scattering matrix theory, density functional theory (DFT), quantum molecular dynamics and quantum Monte Carlo methods. We have developed a state-of-the-art technique by combining NEGF with DFT for first principles simulations of realistic nanoelectronic devices including atomistic details of the device material. We are currently investigating various issues of nonequilibrium quantum transport of charge and spin in nanoelectronics, including magnetic tunnel junctions, molecular electronics, carbon nanostructures, nanowires, Kondo physics, and strongly correlated electrons in quantum dots.


• “Ab initio simulation of magnetic tunnel junctions”, D. Waldron, L. Liu and H. Guo,

in Molecular and biological devices, special issue of Nanotechnology 18, 424026 (2007).

• “Low field phase diagram of spin Hall effect in the mesoscopic regime”, Z. Qiao, W. Ren, J. Wang and H. Guo, Phys. Rev. Lett. 98, 196402 (2007).

• “First principles modeling of tunnel magnetoresistance of Fe/MgO/Fe trilayers”, D. Waldron, V. Timoshevskii, Y. Hu, K. Xia and H. Guo, Phys. Rev. Lett. 97, 226802 (2006).

• “Time-dependent quantum transport far from equilibrium: an exact nonlinear response theory”, J. Maciejko, J. Wang and H. Guo, Phys. Rev. B 74, 085324 (2006).

• “Nonlinear spin-current and magnetoresistance of molecular tunnel junctions”, D. Waldron, P. Haney, B. Larade, A. MacDonald and H. Guo, Phys. Rev. Lett. 96, 166804 (2006).

Honors and awards

2007: Fellow of Royal Society of Canada2006: Brockhouse Medal of the Canadian Association of Physicists,

for Outstanding Experimental or Theoretical Contributions to Condensed Matter and Materials Physics

2005: David Thomson Award for Excellence in Graduate Supervision & Teaching, McGill University

2004: Killam Research Fellowship Award, Canadian Council for Arts2004: Elected to Fellow of The American Physical Society2004: James McGill Professor, McGill University2000 - present: Honorary Professor, University of Hong Kong


Canadian Association of Physicists (CAP)American Physics Society (APS)Materials Research Society (MRS)Oversea’s Chinese Physicists Association (OCPA)

Research keywords

Nanoelectronics, quantum transport theory, mesoscopic physics, computational physics

Name: Subhash GujrathiAffiliations: Professor, Department of Physics, Dawson College Montreal; Invited researcher, Department of Physics and Member, Groupe de Recherche en Physique et Technologie des Couches Minces (GCM), Université de Montréal Diploma: Ph.D., Physics, 1968, University of Calcutta, IndiaEmail: [email protected]

Name: Hong GuoAffiliations: Professor, Department of Physics; James McGill professor; and Director, Centre for the Physics of Materials, McGill University; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Physics, 1987, University of Pittsburgh, USAEmail: [email protected]: www.physics.mcgill.ca/~guo/

27 | RQMP | MeMbeRs

GUjRAThI s. GUO h.

Research interests

Our group focuses on novel phenomena where quantum effects are dominant. The topics and tools used in our research include:

• New materials: semiconductor heterostructures (GaAs/AlGaAs, InGaAs/InAlAs, Ge/SiGe), carbon nanotubes, graphene, MgB2, microstructured superconductors, metallic glasses

• Experimental techniques: low temperatures (dilution refrigerator, He3 system), high frequencies (<50GHz), nanofabrication (AFM lithography), semiconductor processing, transport measurements (electrical and thermal)

• Modeling techniques: transport properties, disordered systems, interactions effects

• Physics: quantum Hall effects, strongly correlated electrons, quantum comput-ing (decoherence), superconductivity, nanoelectronics, coupled quantum dots, quantum phase transitions, dynamics in quantum systems.


• “Density of states of disordered systems with a finite correlation length”, J.C. Flores and M. Hilke, Phys. Rev. B 73, 125115 (2006).

• “Two-dimensional electron gas in InGaAs/InAlAs quantum wells”, E. Diez, Y. P. Chen, S. Avesque, M. Hilke, E. Peled, D. Shahar, J. M. Cerver, D. L. Sivco and A. Y. Cho, Appl. Phys. Lett. 88, 052107 (2006).

• “Transverse vortex dynamics in superconductors”, J. Lefebvre, M. Hilke, R. Gagnon and Z. Altounian, Phys. Rev. B 74, 174509 (2006).

• “The microwave induced resistance response of a high mobility 2DEG from the quasi-classical limit to the quantum Hall regime”, S.A. Studenikin, M. Byszewski, D.K. Maude, M. Potemski, A. Sachrajda, Z.R. Wasilewski, M. Hilke, L.N. Pfeiffer and K.W. West, Physica E 34, 73 (2006).

• “Decoherence in a N -qubit solid-state quantum register”, B. Ischi, M. Hilke and M. Dube, Phys. Rev. B 71, 195325 (2005).

Honors and awards

2001: FCAR strategic professorship1996: Swiss National Science Foundation Post-Doc Fellowship,

Princeton University



Research keywords

Quantum computing, quantum Hall effect, quantum materials, superconductivity, high speed nanoelectronics

Research Interests

• Radiation damage (proton, neutron) on Si detectors for the Large Hadron Collider (LHC) at CERN; development of radiation-tolerant detectors for the LHC

• Studies of proton resistance of new detector arrays (MDX) for medical applications

• Nuclear physics applications for detection techniques and quantitative measurements of water levels (collaboration with IREQ)

• Detection and measurements of water by low-energy photons absorption in various materials, such as industrial plywood


• “Modified Hecht model qualifying radiation damage in standard and oxygenated silicon detectors from 10 MeV protons”, A. Charbonnier, S. Charron, A. Houdayer, C. Lebel, C. Leroy, V. Linhart and S. Pospisil, Nucl. Instr. and Meth. A 576, 75 (2007).

• “Development of an unattended Gamma Monitor with custom electronic for the Determination of Snow Water Equivalent (SWE) using the Natural Ground Gamma Radiation”, A. Houdayer, J.P. Martin, C. Lebel, Y. Choquette, P. Lavigne and P. Ducharme, IEEE Nucl. Science, 2007.

• “Low-Energy Protons Scanning of Intentionally Partially Damaged Silicon MESA Radiation”, A. Houdayer, C. Lebel, C. Leroy, V. Linhart and S. Pospisil, IEEE Nucl. Science 51, 3838 (2006).

• “Radiation-hard semiconductor detectors for Super-LHC”, M. Bruzzi, A. Houdayer, C. Lebel, C. Leroy, et al., Nucl. Instr. and Meth. A 541, 189 (2005).

• “Development of radiation tolerant semiconductor detectors for the S uper-LHC”, M. Moll, A. Houdayer, C. Lebel, C. Leroy, et al., Nucl. Instr. and Meth. A 546, 99 (2005).

Professionnal affiliation

Canadian Association of Physicists (CAP)

Research keywords

Applied physics, radiation damage, detectors

Name: Michael HilkeAfiliations: Associate Professor, Department of Physics, McGill University; Director, Institut Trans-disciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Physics, 1996, University of Geneva, SwitzerlandEmail: [email protected]: www.physics.mcgill.ca/~hilke

Name: Alain HoudayerAffiliations: Invited researcher, Department of Physics, Université de MontréalDiploma: Ph.D., Physics, 1972, McGill University, Montreal, CanadaEmail: [email protected]

28 | RQMP | MeMbeRs

hILKe M. hOUDAyeR A.

Research interests

We use optical techniques, such as light inelastic scattering, luminescence and infrared interferometry, to study microscopic interactions within the following solids:

1. Magnetoresistive manganites of the type R(1-x)A(x)MnO3 (R=rare earth, A=Ba, Ca, Sr) in which a remarkable resistivity drop occurs following the application of a magnetic field. These materials are important both at the fundamental level, because of the strong couplings between the charges, spins and ions, and at the applied level, in the fields of magnetic recording, readback compo-nents and for spin polarized electronics.

2. High Tc superconductors of the type R(2-x)Ce(x)CuO4, characterized by the absence of resistance and the prevalence of perfect diamagnetism at tempera-tures lower than the critical temperature. These materials allow the transport of the current without loss, the generation of intense magnetic fields and the detection of very weak magnetic fields.

3. Optical components such as solid lasers and optical memories containing rare earths of the type Nd:YVO4 and Yb:Y2SiO5. Rare earths (Pr, Nd, Sm…) are incorporated in all these materials. We use both light diffusion and infrared spectroscopy to detect the vibrations of the ions and the 4f electronic levels of the rare earth electrons. These levels are used to locally probe various electron-electron, electron-ion and ion-ion interactions.


• “Annealing optical effects on Yb-doped Y2SiO5 thin films”, A. Denoyer, S. Jandl, F. Thibault and D. Pelenc, J. Phys: Condens. Matter 19, 156222 (2007).

• “Raman study of κ−ET2Cu[N(CN)2]Cl at ambient and ~ 300 bars pressures”, K.D. Truong, S.Jandl and M.Poirier, Synthetic Metals 157, (2007).

• “Optical properties of Yb-doped Y2SiO5 thin films”, A. Denoyer, S. Jandl, B. Viana, O. Guillot-Noël, P. Goldner, D. Pelenc and F. Thibault, Optical Materials 30, 416 (2007).

• “Multiple-order Raman Scattering from Rare earth Manganites: Oxygen isotope and Rare Earth Substitution Effects”, M. N. Iliev, V. G. Hadjiev, A. P. Litvinchuk, F. Yen, Y. Q. Wang, Y. Y. Sun, S. Jandl, J. Laverdière, V. N. Popov and M. M. Gospodinov, Phys Rev B 75, 064303 (2007).

• “Infrared Study in High magnetic Fields of the Crystal-Field Excitations in PrMnO3”, S. Jandl, V. Nekvasil, A. A. Mukhin and M. L. Sadowski, J. of Magnetism and Magnetic Materials 311, 583 (2007).

Research keywords

Raman spectroscopy, infrared spectroscopy, crystal fields, superconductors, manganites

Research interests

The Kilfoil Research Group uses several microscopy techniques, optical and mechanical manipulation tools to study structure, dynamics and mechanical properties of soft condensed matter systems such as glasses and gels, and biophysical systems in vitro and inside living cells.

A major component of Kilfoil’s experimental toolkit is confocal fluorescence miscroscopy capable of image stack acquisition at controlled time intervals at unprecedented fast rates, in tandem with sophisticated feature-finding and tracking algorithms to study the dynamics at the single particle level of systems approaching solid phase transitions, often to nonequilibrium solid phases. She also uses videomicroscopy of probe particles embedded in reconstituted cell cytoskeleton to help develop models for cell mechanics.

Kilfoil and her team have extended their expertise in high-resolution feature-finding and tracking to confocal image data acquired in living cells and have developed new tools to extend the range of objects that can be automatically tracked to include microtubule filaments, as well as the cell periphery, in three dimensions. Her team applies new these microscopy tools to study the dynamics of cell cytoskeletal elements as cells orchestrate the positioning of the nucleus for proper chromosome segregation and establish the asymmetric bias commonly essential to this process, during cell division.


• “Direct Observation of Dynamical Heterogeneities Near the Colloidal Gel Transition”, Y. Gao and M.L. Kilfoil, Physical Review Letters 99, 078301 (2007).

• “Time-dependent viscoelastic shear modulus during gravitational collapse of colloidal gels”, S.W. Kamp and M.L. Kilfoil, in press Soft Matter (2007).

• “Dynamics of Weakly Aggregated Colloidal Particles”, M.L. Kilfoil, E.E. Pashkovski, J.G. Masters and D.A. Weitz, Philosophical Transactions: Mathematical, Physical and Engineering

Sciences 361, 753 (2003).

• “Direct measurement of the alignment tensor for a polymer melt under strong shearing flow”, M.L. Kilfoil and P.T. Callaghan, Macromolecules 33, 287 (2000).

• “Chain deformation for a polymer melt under shear”, P.T. Callaghan, M.L. Kilfoil and E.T. Samulski, Physical Review Letters 81, 4524 (1998).

Honors and awards

2002: Harvard University Materials Research Science and Engineering Centre Postdoctoral Fellowship

2001: National Sciences and Engineering Research Council of Canada (NSERC) Postdoctoral Fellowship, tenure of award Harvard University

2000: J. Bruce and Helen H. French Graduate Scholarship in Physics, Memorial University 2000: A.G. Hatcher Memorial Scholarship, Memorial University

1999: New Brunswick Women’s Doctoral Fellowship1998: NSERC Post Graduate Studies Award1996: Fellow, School of Graduate Studies, Memorial University


American Physical Society (APS)Biophysical SocietyCanadian Association of Physicists (CAP)American Association for the Advancement of Science (AAAS)

Research keywords

Soft condensed matter, optical microscopy, biophysics, colloids, rheology

Name: Serge JandlAffilations: Professor, Department of Physics, Université de SherbrookeDiploma: Ph.D., Physics, 1974, Université de Montréal; Docteur d’État ès Sciences, 1976, Université de Grenoble, FranceEmail: [email protected]

Name: Maria Kilfoil Affiliation: Professor, Department of Physics, McGill UniversityDiploma: Ph.D., Physics, 2001, Memorial University, CanadaEmail: [email protected]: www.physics.mcgill.ca/~kilfoilgroupsplash.shtml

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jANDL s. KILfOIL M.

Research interests

We develop new nanocomposite (nc) coatings formed by metal nitride or metal carbon-nitride nano-particles (1-20 nm in size) imbedded in an amorphous matrix (e.g. silicon nitride, silicon carbon-nitride, ...) fabricated by different physical vapor (PVD), plasma-enhanced chemical vapor (PECVD) and hybrid (PVD/PECVD) pro-cesses. Particular aim is to obtain unique properties such as superhardness, very high toughness and thermal stability, combined with excellent tribological (high wear and erosion resistance) and corrosion resistance characteristics suitable for applications in aerospace, automotive, biomedical and numerous other areas. We have been very active in collaborating with the aerospace and manufacturing industry in Canada (e.g. CRIAQ and its industrial members).

In our specialized laboratory for tribo-mechanical testing, we have developed expertise for full tribo-mechanical analysis and evaluation of elasto-plastic properties in a very broad load range of loads and distances. We now particularly investigate thin film mechanical properties on nanometer scale with a main focus on nanotribological and nanohardness testing using depth-sensing indentation, micro- and nano-scratching, wear testing and image analysis with high depth resolution suitable for testing functional thin film materials for aerospace, manufacturing, optics and photonics, microelectronics, biomedical and other applications.

We contributed significantly to the understanding of the effect of plasma treatment of polymers for surface functionalization, activation and adhesion enhancement in polymer/polymer, inorganic dielectric film/polymer and metal/polymer systems.


• “Tailoring the Adhesion of Optical Films on Polymethyl-methacrylate by Plasma-induced Surface Stabilization”, E. Klemberg-Sapieha, L. Martinu, N.L.S. Yamasaki and C.W. Lantman, Thin Solid Films 476, 101 (2005).

• “Quartenary Hard Nanocomposite TiCN/SiCN Coatings Prepared by PECVD”, P. Jedrzejowski, J.E. Klemberg-Sapieha and L. Martinu, Thin Solid Films 466, 189 (2004).

• “Microstructure of Plasma-Deposited SiO2/TiO2 Optical Films”, S. Larouche, H. Szymanowski, J.E. Klemberg-Sapieha, L. Martinu and S. Gujrathi, J. Vac. Sci. Technol. A 22, 1200 (2004).

• “Mechanical Characteristics of Optical Coatings Prepared by Different Techniques: A Comparative Study”, J.E. Klemberg-Sapieha, J. Oberste-Berghaus, L. Martinu, R. Blacker, I. Stevenson, G. Sadkhin, D. Morton, S. McEldowney, B. Klinger, P. Martin, N. Court, S. Dligatch, M. Gross and R.P. Netterfield, Applied Optics 43, 2670 (2004).

• “Microstructure and Mechanical Properties of Plasma Deposited Ultrahard TiN/SiN1.3 Nano-Composite Films”, P. Jedrzejowski, J.E. Klemberg-Sapieha and L. Martinu, Thin Solid Films 426, 150 (2003).


American Chemical Society (ACS)American Physical Society (APS)American Vacuum Society (AVS)Society of Vacuum Coaters (SVC)Société de Microscopie du CanadaSigma Xi-Research Society of North America

Research keywords

Superhard nanocomposite and protective coatings, surface and interface, tribo-corrosion, mechanical properties, plasma processing

Research interests

The Lennox research group is oriented towards the synthesis, characterization, and implementation of nanoscale materials. The nanoscale materials of interest include gold nanoparticles, self assembled monolayers on gold, and block copo-lymers. In the case of gold nanoparticles, we are interested in understanding how and why they form. Although the number of gold nanoparticle publications has risen form ca. 10 p.a. in 1993 to ca. 2000 p.a. in 2005, few if any deal with the ongoing problem of polydispersity and nanoparticle morphology. We are currently addressing this problem by assessing the relationships between particle interfacial energy, charge distribution, and the equilibrium electronic state. Applications of these gold nanoparticles in our laboratory include use as tracers in polymer melts and cell biology. In our self assembled monolayer work we are trying to understand the relationships between phase separation in the nm-thick film Function related to the films electrical resistance. Block co-polymers are used as both templates and masks to create structures in surfaces whose lengthscales are invariably on the nanoscale. In related work we exploit our recently-developed gold precursors for the precise positioning of gold nanoparticles on surfaces. Applications in photonics biosensors are being pursued with these patterned gold nanoparticles.


• “Surface Plasmon Resonance of Au Nanoparticle Arrays Partially Embedded into Quartz Substrates”, V. Meli and R.B. Lennox, J. Phys. Chem C 111, 3658 (2007).

• “Uniform One-Dimensional Arrays of Tunable Gold Nanoparticles with Tunable Interparticle Distances”, M.K. Corbierre, J. Beerens, J. Beauvais and R.B. Lennox Chem. Mater. 18, 2628 (2006).

• “Place Exchange Reactions of n-Alkylthiols on Gold Nanoparticles”, A. Kassam, G. Bremner, G. Ulibarri, B. Clark and R.B. Lennox, J. Am. Chem. Soc. 128, 3746 (2006).

• “Surface Plasmon Resonance Spectroscopy Study of Electrostatically Adsorbed Layers”, V. Gandubert and R.B. Lennox, Langmuir 22, 4589 (2006).

• “Adsorption of Alkylthiol-Capped Gold Nnaoparticles onto Alkylthiol SAMs: An SPR Study”, M. Goren and R.B. Lennox, Langmuir 22, 341 (2006).

Honors and awards

2005: Tomlinson Chair in Chemistry, McGill University2002: CERSIM Lecturer


Chemical Institute of CanadaAmerican Chemical Society

Keywords

Nanoscale materials, gold nanoparticules, self assembled monolayers, block copolymers, photonics biosensors

Name: Jolanta Klemberg-SapiehaAffiliations: Senior Research Scientist, Department of Engineering Physics; Associate Director: Functional Coating and Surface Engineering Laboratory (FCSEL-LaRFIS); and Co-director and Co-founder: Laboratory for Optical and Tribo-mechanical Metrology, École Polytechnique de MontréalDiploma: Ph.D., Materials Science, 2000, Technical University of Lodz, Poland Email: [email protected]: www.polymtl.ca/larfis

Name: Robert Bruce LennoxAffiliation: Tomlinson Professor of Chemistry and Chair, Department of Chemistry, McGill University; Member, Centre for Self-Assembled Chemical StructuresDiploma: Ph.D., Chemistry, 1985, University of Toron to; Email: [email protected]: www.chemistry.mcgill.ca

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KLeMbeRG-sAPIehA j. LeNNOx R.b.

Research interests

The activities of the experimental research group directed by Leonelli are centered on the study of the electronic properties of novel semiconductor materials and of the new physics that emerges when they are assembled into nanostructures. We are especially interested in exciton relaxation dynamics in zero-dimensional systems: How are excitons captured and released in “quantum dots”? On what timescale do they interact with phonons? How do they lose coherence? Answers to these questions not only shine light on fundamental physical processes but also pave the way for improved devices for optoelectronics and information processing applications.

The experimental tools at the disposal of the Leonelli Research Group include several optical spectrometers and a variety of excitation sources, including a CW and a pulsed tunable Ti:sapphire lasers, that allow to perform absorption, modulated reflectance, photoluminescence, photoluminescence excitation and Raman scattering experiments. We strive to push the setups at their resolution and sensitivity limits over a spectral range that extends from 300 to 2 500 nm.


• “Experimental and theoretical studies of the E+ optical transition in GaAsN alloys”, V. Timoshevskii, M. Côté, G. Gilbert, R. Leonelli, S. Turcotte, J.-N. Beaudry, P. Desjardins, S. Larouche, L. Martinu, and R. A. Masut, Phys. Rev. B 74, 165120 (2006).

• “Raman study of optical phonons in ultrathin InAs/InP single strained quantum wells”, A. Lanacer, J. F. Chabot, M. Côté, R. Leonelli, D. Frankland, and R. A. Masut, Phys. Rev. B 72, 075349 (2005).

• “Evidence for large configuration-induced band-gap fluctuations in GaAsN alloy”, G. Bentoumi, V. Timoshevskii, N. Madini, M. Côté, R. Leonelli, J.-N. Beaudry, P. Desjardins, and R. A. Masut, Phys. Rev. B 70, 035315 (2004).

• “Excitons in ultrathin InAs/InP quantum wells: Interplay between extended and localized states”, P. Paki, R. Leonelli, L. Isnard, and R. A. Masut, J. Vac. Sci. Technol. A 18, 956 (2000).

• “Optical properties of submonolayer InAs/InP quantum dots on vicinal surfaces”, P. Paki, R. Leonelli, L. Isnard, and R. A. Masut, J. Appl. Phys. 86, 6789 (1999).

Honors and awards

2008: Award fo Excellence in Teaching, Université de Montréal


Canadian Association of PhysicistsAmerican Physical Society

Research keywords

Semiconductors, excitons, nanostructures, photoluminescence, quantum dots

Research interests

Our research program consists of studying the effects of the atomic structure of matter on the electronic, optical and mechanical properties of low symmetry materials - often called “new materials” - in particular nanomaterials and nano-structured materials. At such a small scale, the traditional tools become inappro-priate because of the low symmetry of the systems under study. Our approach is to build models from fundamental constituents of the matter, atoms and electrons, meant to describe materials as realistically as possible. We use several types of models, ranging from a completely empirical approach to ab initio calculations, including semi-empirical or semi-quantum approaches. The choice of the model varies according to the problem considered and in particular, on the length and time scales of the problem under investigation.

Following a selection of problems which we are currently studying:

• Surface and volume diffusion of impurities and defects • Thermodynamic of nanoagregates• Self-organization of aggregates under constraints • Mechanisms of laser ablation• Phase segregation in binary alloys• Defects in a-Si


• “Kinetic faceting and anomalous coarsening in elastically inhomogeneous multiphase systems”, D. Perez and L.J. Lewis, Phys. Rev. Lett. 98, 07501 (2007).

• “Ablation of molecular solids under nanosecond laser pulses: The role of inertial confinement”, D. Perez, P. Lorazo, L.J. Lewis and M. Meunier, Appl. Phys. Lett. 89, 141907 (2006).

• “Coulomb explosion induced by intense ultrashort laser pulses in two-dimensional clusters”, V. Mijoule, L.J. Lewis and M. Meunier, Phys. Rev. A 73, 033203 (2006);

see also Virtual Journal of Ultrafast Science 5(4).

• “Stable fourfold configurations for small vacancy clusters in silicon from ab initio simulations”, D.V. Makhov and L.J. Lewis, Phys. Rev. Lett. 92, 255504 (2004).

• “Short-pulse laser ablation of solids: from phase explosion to fragmentation”, P. Lorazo, L.J. Lewis and M. Meunier, Phys. Rev. Lett. 91, 225502 (2003);

see also Virtual Journal of Ultrafast Science 2(12).

Research keywords

Numerical physics, amorphous materials, laser-matter interactions, nanomaterials

Name: Richard Leonelli Affiliation: Professor, Department of Physics; Co-director, Laboratoire de caractérisation des matériaux, Université de MontréalDiploma: Ph.D., Physics, 1985, Université de Montréal, CanadaEmail: [email protected]: www.mapageweb.umontreal.ca/leonelli

Name: Laurent J. Lewis Affiliation: Professor, Department of Physics, Associate Dean, Faculty of Arts and Sciences, Université de MontréalDiploma: Ph.D., Physics, 1983, McGill University, Montreal, CanadaEmail: [email protected]: www.esi.umontreal.ca/~grofnum

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LeONeLLI R. LewIs L.

Research interests

The Lupien Research Group is developing very low temperature scanning tunneling microscopes to study fundamental problems in the field of strongly correlated electrons such as the high-critical temperature superconductors. This type of instruments allows to image atoms at the surface of samples and to study the electronic organization at the atomic scale.

The research aims to discover and study the nanoscale reorganization of electrons that often occur in strongly correlated electrons materials. Comparing the experimental data with the various theories should yield a better fundamental understanding of these systems. This could, in turn, permit a better use of these materials and their interesting properties.

The group also works to push the limits of the technique to lower temperatures, higher magnetic fields and to new nanoscale probes.


• “An Intrinsic Bond-Centered Electronic Glass with Unidirectional Domains in Underdoped Cuprates”, Y. Kohsaka, C. Taylor, K. Fujita, A. Schmidt, C. Lupien, T. Hanaguri, M. Azuma, M. Takano, H. Eisaki, H. Takagi, S. Uchida and J. C. Davis, Science 315, 1380 (2007).

• “A ‘checkerboard’ electronic crystal state in lightly hole-doped Ca2-xNaxCuO2Cl2”, T. Hanaguri, C. Lupien, Y. Kohsaka, D.-H. Lee, M. Azuma, M. Takano, H. Takagi and J. C. Davis, Nature 430, 1001 (2004).

• “Transport in ultraclean YBa2Cu3O7: neither unitary nor Born impurity scattering”, R. W. Hill, C. Lupien, M. Sutherland, E. Boaknin, D. G. Hawthorn, C. Proust, F. Ronning, L. Taillefer, R. Liang, D. A. Bonn and W. N. Hardy, Physical Review Letters 92, 027001 (2004).

• “Field-induced thermal metal-to-insulator transition in underdoped La2-xSrxCuO4”, D. G. Hawthorn, R. W. Hill, C. Proust, F. Ronning, M. Sutherland, E. Boaknin, C. Lupien, M. A. Tanatar, J. Paglione, S. Wakimoto, H. Zhang, L. Taillefer, T. Kimura, M. Nohara, H. Takagi and N. E. Hussey, Physical Review Letters 90, 197004 (2003).

• “STM studies of individual Ti impurity atoms in Sr2RuO4”, B. I. Barker, S. K. Dutta, C. Lupien, P. L. McEuen, N. Kikugawa, Y. Maeno and J. C. Davis, Physica B 329-333, 1334 (2003).

Honors and awards

2005: Lee-Osheroff-Richardson North American Prize for Low temperature and high magnetic field research, sponsored by Oxford Instruments Supercon-ductivity

2002: Postdoctoral fellowship, Natural Sciences and Engineering Research Council of Canada (NSERC), University of California at Berkeley and Cornell University

2000: E. F. Burton Fellowship, University of Toronto2000: Walter C. Sumner memorial fellowship, University of Toronto

Professionnal; affiliations

Canadian Association of Physicists (CAP)American Physics Society (APS)Association francophone pour le savoir (ACFAS)

Research keywords

Superconductivity, scanning tunneling microscopy/spectrroscopy, low temperatures, strongly correlated electrons

Research interests Professor Maciejko’s Group (The Optoelectronics Laboratory) develops software, devices and systems for various applications using the photonic technology and applies them to problems in telecommunications and biology.

The group’s interests cover both theoretical and experimental aspects of photonic device research. A world-class semiconductor laser simulator used in industry and in government labs was produced. It was used to develop semiconductor amplifiers and broadband sources for biological and telecommunications applications. Also, various problems such as laser linewidth broadening, fiber-based lasers, mode-locking in Cr-YaG lasers, device integration, near-field and two-photon microscopy were investi-gated as well as carrier dynamics with Monte-Carlo simulation and with femtosecond time-resolved photoluminescence.

In biological applications, the group developed an optical coherence tomography (OCT) system aimed at the non-invasive imaging of tissues for fundamental research and for histo-pathological determination. Collaborations with NRC in investigating speckle OCT and elastography are underway. Another aim of the laboratory is to develop multi-imaging modality and to compare the data provided by X-rays, ultrasound, OCT, two-photon and RMN. A Doppler OCT system for the characterization of liquid flow in various structures was developed. This technology provides unprecedented resolution and is foreseen to become a powerful new tool for the investigation of microfluidic circuits.

Selected publications• “A Comparative Study of Several Optical Sources in the Near Infrared for OCT

Applications”, L. Carrion, M. Lestrade, Z. Xu, G. Touma, R. Maciejko and M. Bertrand, Jour. Biomed. Optics 12, 1 (2007).

• “Novel S+C+L broadband source based on semiconductor optical amplifiers and erbium-doped fiber for optical coherence tomography”, D. Beitel, L. Carrion, K. L. Lee, A. Jain, L. R. Chen, R. Maciejko and A. Nirmalathas, Conference on Lasers and Electro-Optics (CLEO’07), Baltimore, Maryland, 6-11 May 2007.

• “Degradation of side-mode suppression ratio in a DFB laser integrated with a semiconductor optical amplifier”, A. Champagne, M. Lestrade, J. Camel, R. Maciejko and B. Tromborg, IEEE Journal of Quantum Electronics 40, 871 (2004).

• “Promising intracavity mode-locking device: a strained GaInAs/AlInAs saturable Bragg reflector grown by molecular-beam epitaxy”, Y. Chang, R. Leonelli, R. Maciejko, and A. SpringThorpe, Applied Phys. Lett. 76, 921 (2000).

• “Photoluminescence study of carrier dynamics and recombination in a strained InGaAsP/InP multiple-quantum-well structure”, A.D. Güçlü, C. Rejeb, R. Maciejko, D. Morris and A. Champagne, Jour. of Applied Physics 86, 3391 (1999).

Honors and awardsAssociate Editor: Canadian Journal of Physics (2007- ...) • Grant Selection Committee on Team Research Projects, FQRNT, (2007) • Technical Co-Chair of Photonics North (2006) • Administration Board of CIPI (Canadian Institute for Photonic Innovation, a Network of Centers of Excellence) • Group leader in the CIPI, Centre of Excellence • Technical Co-Chair of Photonics North 2003 • Nomination au Prix Roberval (France), 2003 • Administration Board of the Montreal Photonics Network (and Quebec Photonics Network) • Administration Board of FEMTOTECH, (Valorisation Recherche Québec) • Senior member of IEEE and member of other societies • Member of the NSERC Electri-cal Engineering G.S.C. • Prize for Teaching, École Polytechnique; 3 times. (2000-2003) • Prize for Research 2000, École Polytechnique, Prix Poly 1873 • Academic Council at the University • Committee of Experts to evaluate the National Optics Institute • Senior Industrial Fellow, NSERC, (1991-1992) • Industrial Post-doctoral Fellowship, NSERC, (1978-1980) • Research Fellowship, SUNY, Stony Brook, (1970-1975) • Research Fel-lowship in Mathematics, Indiana University, (1969) • Medal of the Governor-General of Canada, (1966) • PFIZER Prize awarded by ACFAS, (1966) • Third Prize of the Canadian Mathematical Society, (1965) • External reviewer for the Steacie Memorial Fellowship

Professional affiliationsInstitute of Electrical and Electronics Engineers (IEEE)American Physics Society (APS)

Research keywords Optical coherence tomography, photonic devices, laser simulation, fiber optics, biomedical imaging

Name: Christian LupienAffiliation: Assistant professor, Department of Physics, Université de SherbrookeDiploma: Ph.D., Physics, 2002 University of Toronto, CanadaEmail: [email protected]: www.physique.usherbrooke.ca/lupien/

Name: Romain MaciejkoAffiliations: Professor and Director of Undergraduate Studies; Chair of Program Committee; and Member of Executive Committee, Department of Engineering Physics, École Polytechnique de MontréalDiploma: Ph.D., Physics, 1975, Stony Brook, USAEmail: [email protected]: http://maxwell.phys.polymtl.ca

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LUPIeN C. MACIejKO R.

Research interests

Our research aims to advance the chemistry and physics of electroactive nano-structures, and to study the phenomena occurring at their surfaces and interfaces. Novel nanomaterials such as nanotubes, nanowires and supramolecular nano-structures are studied using surface sensitive techniques (UPS, AES, XPS, HREELS, IRAS), transport experiments (IV curves and magnetoresistance with temperature) and proximal probes (STM and AFM). In addition, we use techniques borrowed from microelectronics to construct prototype nanodevices and explore possible applications of one-dimensional nanomaterials for electronics, optoelectronics, sensing technologies and energy conversion.


• “Small molecule light emitting diodes on carbon nanotube electrodes”, C. M. Aguirre, S. Auvray, S. Pigeon, R. Izquierdo, P. Desjardins and R. Martel, Appl. Phys. Lett. 88, 183104 (2006).

• “Probing the Reversibility of Sidewall Functionalization Using Carbon Nanotube Transistors”, J. Cabana and R. Martel, J. Am. Chem. Soc 129, 2244 (2007).

• “Raman studies of single-wall carbon nanotube salts in solutions”, E. Anglaret, F. Dragin, A. Pénicau and R. Martel, J. Phys. Chem. B 110, 3949 (2006).

• “Exciton formation and annihilation during 1D impact excitation in carbon nanotubes”, L. Marty, E. Adam, L. Albert, R. Doyon, D. Ménard and R. Martel, Phys. Rev. Lett. 96, 136803 (2006).

• “Ultrafast Dynamics of the Mid-Infrared Response of Carbon Nanotubes”, L. Perfetti, T. Kampfrath, F. Schapper, A. Hagen, T. Hertel, C. Aguirre, P. Desjardins, R. Martel, C. Frischkorn and M. Wolf, Phys. Rev. Lett. 96, 027401 (2006).

Honors and awards

2006: Top Ten Discoveries of the Year, magazine Québec Science2006: Fellow of the American Physical Society, For seminal advances in

understanding and exploiting the electrical and optical properties of individual carbon nanotubes

2004: IBM Research Division Award (RDA): electro-optical properties of nanotube.2003: ISSCC 2003 Jack Raper Outstanding Technology Directions Paper Award

for the paper Carbon Nanotube Field Effect Transistors - Fabrication, Device Physics, and Circuit Implications” (Feb 2004)

2003: Canada Research Chair on Electricity-conducting Interfaces and Nanostructures (Tier II)

2002: IBM Outstanding Technical Achievement Awards for Breakthroughs in molecular and nanoelectronics

2002: Voted co-finalist for The 2002 World Technology Award for Materials, July 2002

2001: Two Patent Invention Achievement Awards, Feb. 2001 (First patent) and Sept. 2002 (First Plateau)

2000: IBM Outstanding Technical Achievement Awards for Electronic transport in carbon nanotubes


American Physics Society (APS)American Physical Society (ACS)American Association for the Advance in Science (AAAS)American Vacuum Society (AVS)

Research keywords

Nanoscience, nanoelectronics, carbon nanotubes, electroluminescence

Research interests

The main research interest of L. Martinu is the development of new processes and materials for thin film systems and devices with tailored optical, optoelectronic, mechanical, tribological, protective, electrical and other properties for their application is optics, photonics, biomedical, aerospace and other areas. An essential part of his research is the investigation of the surface and near-surface processes during the film growth, and the engineering of surfaces and interfaces.

He particularly focuses on the development of complementary low pressure plasma-based technologies, including plasma enhanced chemical vapor deposi-tion, pulsed multi-magnetron sputtering, dual ion beam sputtering, cathodic arc deposition and hybrid CVD/PVD processes, aimed at the fabrication of thin film systems based on specifically designed multilayer, graded layer and nanocompos-ite architectures applied to 2D and 3D platforms, including particulates and con-tinuous webs. Recent contributions include graded index (rugate) optical filters, optical filters for security devices (optically variable devices) and all-optical gas sensors, protective coating solutions for aircraft components, biomedical devices and instrumentation, and spectacle lenses, decorative coatings, and superhard corrosion resistant coatings for manufacturing processes. Important part of his research is devoted to coating plastic substrates, to in situ real time diagnostics (e.g. spectroscopic ellipsometry, ion/mass spectrometry, mathematical modeling and simulation), and to the metrology of the optical and mechanical properties of thin films.


• “Ion-Surface Interactions on c-Si (001) at the Radiofrequency-Powered Electrode in Low-Pressure Plasmas: Ex Situ Spectroscopic Ellipsometry and Monte-Carlo Simulation Study”, Amassian, P. Desjardins and L. Martinu, J. Vac. Sci. Technol. A 24, 45 (2005).

• “Pulsed RF PECVD of a-SiNx:H alloys: properties, growth mechanism and applications”, R. Vernhes, O. Zabeida, J.E. Klemberg-Sapieha and L. Martinu, J. Appl. Phys. 100, 63308 (2006).

• “Microstructure of Plasma-Deposited SiO2/TiO2 Optical Films”, S. Larouche, H. Szymanowski, J.E. Klemberg-Sapieha, L. Martinu and S. Gujrathi, J. Vac. Sci. Technol. A 22, 1200 (2004).

• “Optical Coatings on Plastics”, L. Martinu and J.E. Klemberg-Sapieha, in Optical Interference Filters, N. Kaiser and H. Pulker, eds.,

Spinger, Berlin 2004, 460-489.

• “Single Material Inhomogeneous Optical Filters Based on Microstructural Gradients in Plasma Deposited Silicon Nitride”, R. Vernhes, O. Zabeida, J.E. Klemberg-Sapieha and L. Martinu, Applied Optics 43, 97 (2004).


Member of the Board of Directors – Society of Vacuum CoatersGeneral Program Chair, Student Sponsorship Program Chair – Society of Vacuum CoatersMember of the Board of Directors – ESST-The Upstate New York chapter of the AVS

Research keywords

Optical and tribological coatings, nanostructured thin films, plasma processing, surface and interface engineering, protective coatings

Name: Richard MartelAffiliation: Professor, Department of Chemistry, Université de Montréal; Canada Research Chair on Electricity-conducting Interfaces and NanostructuresDiploma: Ph.D., Chemistry, 1995, Université Laval, Quebec, CanadaEmail: [email protected]

Name: Ludvik Martinu Affiliations: Professor and Chair, Dept. of Engineering Physics, Director and Founder: Functional Coating and Surface Engineer-ing Laboratory (FCSEL-LaRFIS), École Polytechnique de Montréal; Member of the Board of Directors and General Program Chair, Student Sponsorship Program Chair – Society of Vacuum Coaters; Member of the Board of Directors – ESST-The Upstate New York chapter of the AVS; Coordinator of foreign exchange programs with the University of West Bohemia, Czech Republic and the Technical University of Lodz, Poland Diploma: Ph.D., Physics, 1985, Charles University, Prague, Czech Republic; Email: [email protected] Web: www.polymtl.ca/larfis

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MARTeL R. MARTINU L.

Research interests

Our research activities are centered on: (1) The hetero-epitaxial MOVPE/ALE growth of III-V compound semiconductors and strained layers and heterostruc-tures incorporated in advanced electronic and optoelectronic devices, and (2) Thermoelectricity.

They include the growth and device applications of quantum heterostructures and systems of reduced dimensionality, bandgap engineering, strain relaxation and in-terdiffusion in heterostructures. Our contributions range from the heteroepitaxy of various materials systems such as In(Ga)As(P)/In(Ga)P, InP/Si and (In)GaAsN/GaAs for applications in devices such as optical modulators, laser diodes and HIGFETs to more recent work on magnetic semiconductors. Our results have outlined the primordial role of band alignment in the optimization of high frequency Quantum Confined Stark Effect modulators. In reduced dimensionality structures based on the InAs/InP material, we grow and characterize (i) ultrathin quantum wells and superlattices deposited both by Atomic Layer Epitaxy (ALE) and MOVPE, and (ii) self-organized quantum dot multilayers.

More recently we contribute to (i) the characterization of transport phenomena and mechanical properties of bismuth telluride based thermoelectric alloys obtained by powder metallurgy and hot extrusion, and (ii) the development of microfabrication processes to obtain miniaturized thermoelectric modules for high power density cooling applications as well as for thermoelectricity generation.


• “Compositional dependence of the elastic constant of dilute GaAsN alloys”, J-N. Beaudry, N. Shtinkov, R.A. Masut, P. Desjardins and R. Jimenez-Rioboo, J. Appl. Phys. 101, 113507 (2007).

• “Raman study of optical phonons in ultrathin InAs/InP single strained quantum wells”, A. Lanacer, J.F. Chabot, M. Côté, R.Leonelli, D. Frankland and R.A. Masut, Phys. Rev. B 72, 075349 (2005).

• “X-Ray Photoelectron spectroscopyxy and structural analysis of amorphous SiOxNy films deposited at low temperatures”, P. Cova, S. Poulin and R.A. Masut, J. Appl. Phys. 98, 094903 (2005).

• “Evidence for large configuration-induced energy fluctuations in GaAsN alloys”, G. Bentoumi, V. Timochevski, N. Madini, M. Côté, R. Leonelli, N. Beaudry, P. Desjardins, and R.A. Masut, Phys. Rev. B 70, 035315 (2004).

• “Optical and structural properties of InAsP/In(Ga)P multilayers on InP(001): Strained-layer Multiple quantum well structures and devices”, M. Beaudoin, P. Desjardins, R.Y.-F. Yip and R.A. Masut, in InP and Related Compounds, Edited by M.O. Manasreh, Gordon and Breach Science Publishers, pp. 381-458 (2000).

Professionnal affiliation

American Physics Society (APS)

Research keywords

Quantum heterostructures, hetero-epitaxy, dilute nitrides, magnetic semi-conductors, thermoelectricity

Research interests

Our group focuses on electromagnetic properties of magnetic materials, with a special emphasis on microwaves. Materials under study include (but are not limited to): arrays of ferromagnetic nanowires, magnetic nanoclusters embedded in III-V semiconductor epilayers, multiferroic BFCO (Bi2FeCrO6), carbon nanotubes, ultra soft magnetic microwires. Our aim is to use the rich spectrum of magnetic excitations in the microwave range to tailor and engineer the dispersion relation of new materials, for applications in information and communication devices. We are currently setting up a comprehensive facility for the characterization of magnetic properties of materials at high frequencies, including ferromagnetic and spin wave resonance spectroscopy, Brillouin light scattering of magnons, microwave probe stations and magnetometry. Our research themes range from fundamental questions, such as the transport and dynamics of spins in carbon nanotubes, to practical aspects, such as the development of low-cost-ultra sensitive magnetometers for biological applications.


• “Epitaxial Bi2FeCrO6 Multiferroic thin films”, R. Nechache, C. Harnagea, L.-P. Carignan D. Ménard and A. Pignolet, Phil. Mag. Letters 87, 231 (2007).

• “Static and high frequency magnetic and dielectric properties of ferrite-ferroelectric composite materials”, S. Kalarickal, D. Ménard, C. Patton, X. Zhang, L. Sengupta and S. Sengupta, J. Appl. Phys. 100, 084905 (2006).

• “Progress towards the optimization of the signal-to-noise ratio in giant magnetoimpedance sensors”, D. Ménard, G. Rudkowska, L. Clime, P. Ciureanu, A. Yelon, S. Saez, C. Dolabdjian and D. Robbes, Sensors and Actuators A 129, 6 (2006).

• “Exciton Formation and Annihilation during 1D Impact Excitation of Carbon Nanotubes”, L. Marty, E. Adam, L. Albert, R. Doyon, D. Ménard and R. Martel, Phys. Rev. Lett. 96, 13680 (2006).


Ordre des Ingénieurs du Québec (OIQ)American Physics Society (APS)

Research keywords

Magnetism, magnetic materials, ferromagnetic resonance, giant magnetoimpedance, magnetic metamaterials

Name: Remo A. Masut Affiliations: Professor, Department of Physics Engineering; and Director, Laboratoire d’épitaxie et de caractérisation de semi-conducteurs composés (LECSC), École Polytechnique de Montréal Diploma: Ph.D., Physics, 1982, University of Massachusetts, Amherst, USA Email: [email protected]

Name: David MénardAffiliation: Professor, Department of Physics Engineering, École Polytechnique de MontréalDiploma: Ph.D., Engineering Physics, 1999, École Polytechnique de MontréalEmail: [email protected]

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MAsUT R. MéNARD D.

Research Interests

Professor Meunier holds a Canada Research Chair Tier I on Laser micro/nano-engineering of materials which encompasses various research activities, from fundamental laser-material interactions to new laser processing techniques. Research involves the understanding of the basic phenomena of laser–material surface interactions by performing in-situ diagnostic measurements and by mod-eling the interactions using our newly developed models. Lasers are being used for the design and processing of new materials, nanotechnologies, microelec-tronic and optoelectronic circuits, microsystems (MEMS) and biomedical devices. Here are some research themes: (i) Theory of ultrafast laser-materials interaction: Establishment of the thermodynamic behaviour of the ultrafast laser ablation of semiconductors and metals and coulomb explosion due to intense ultrafast laser irradiation. (ii) Laser processes for microelectronics: Development, characteri-sation and modeling of new and patented laser tuning process for analogue microelectronics. (iii) Laser processes for nanotechnologies: Development of new processes based on the laser ablation of a target in liquids to produce contamina-tion-free and stable nanoparticles, magnetic nanoparticles and quantum dots for applications in biomedical imaging and cancer treatment. (iv) Laser processes for microsystems (MEMS): Development a new ultrafast laser process for producing 3-D structures for microfluidic applications. (v) Optical biosensors: New Surface Plasmon Resonance (SPR) approaches for biomedical applications.


• “Fragmentation of colloidal nanoparticles by femtosecond laser-induced super continuum generation”, S. Besner, A. V. Kabashin and M. Meunier, Applied Physics Letters 89, 233122 (2006).

• “Ablation of molecular solids by nanosecond laser pulses: The role of initial confinement”, D. Perrez, P. Lorazo, L. Lewis and M. Meunier, Applied Physics Letters 89, 141907 (2006).

• “Thermodynamics pathways to melting, ablation and crystallization in absorbing solids under short-pulse laser irradiation”, P. Lorazo, L.J. Lewis and M. Meunier, Phys. Rev. B 73, 134108 (2006).

• “Three-dimensional crystallization inside photosensitive glasses by femtosecond laser”, B. Fisette, F. Busque, J-Y Degorce and M. Meunier, Appl. Phys. Lett. 88, 091104 (2006).

• “Stabilization and Size Control of Gold Nanoparticles during Laser Ablation in Aqueous Cyclodextrins”, J.-P. Sylvestre, A. V. Kabashin, E. Sacher, M. Meunier and John H. T. Luong, J. Am. Chem. Soc. 126, 7176 (2004).

Honors and awards

2006: Synergy Price form NSERC for outstanding university-industry collaborations2002: Canada Research Chair in Materials Micro/Nanoengineering Using Lasers

(Tier I)1989: Prix d’excellence du Directeur de l’École Polytechnique1984: NSERC Post-doctoral industrial fellowship1989 to 1999, 2002, 2005, 2008: “Meritas” for excellence in teaching

engineering physics


SPIEOptical Society of America (OSA)Material Research Society (MRS)

Research keywords

Ultrafast laser materials interaction, laser processing for nanotechnologies, laser processing for biomedical applications, laser processing for microelectronics, optical biosensors

Research interests

The Mi Research Group investigates the growth of semiconductor nanostructures, one atom at a time, and builds nanophotonic devices, including quantum dot lasers, single photon source, and terahertz phototransistors, providing enabling solutions to some critical technologies in communications, quantum information processing, solid state lighting, and medical-imaging.

Through the manipulation of individual atoms during molecular beam epitaxial growth, we develop advanced nanoscale heterostructures, such as wetting-layer-free quantum dots, catalyst-free nanowires, III-V nanotubes, and nanomembranes. Such nanostructures, with precisely controlled position, size, geometry, density, and emission wavelength, have been envisaged as the fundamental building blocks for next generation nanoscale devices.

Central to our research is the development of a new generation of nanophotonic devices. Examples of our recent achievements include the world’s first room-temperature quantum dot lasers on Si and the first semiconductor lasers with temperature invariant operation. To bring photonics to CMOS chips and, therefore, to address the fundamental interconnect issue of today’s CMOS technology, we are developing electrically injected nanowire lasers that can be monolithically integrated with Si-electronics. Additionally, our research in mid- and far-infrared quantum dot lasers and visible quantum dot LEDs may, ultimately, have revolu-tionary impacts on medical imaging and solid state lighting.


• “Pseudomorphic and Metamorphic Quantum Dot Heterostructures for Long Wavelength Lasers on GaAs and Si”, Z. Mi and P. Bhattacharya (Invited) IEEE J. Selected Topics in Quantum Electronics on Semiconductor

Photonic Materials 14, 1171 (2008).

• “Quantum Dot Optoelectronic Devices”, P. Bhattacharya and Z. Mi (Invited) Special Issue in Proceedings of the IEEE on Optoelectronic Devices

Based on Quantum Dots 95, 1723 (2007).

• “Enhanced Spontaneous Emission at 1.55 μm from Colloidal PbSe Quantum Dots in a Si Photonic Crystal Microcavity”, Z. Wu, Z. Mi, P. Bhattacharya, T. Zhu and J. Xu, Appl. Phys. Lett. 90, 171105 (2007).

• “Growth and Characteristics of Ultra-low Threshold 1.45 μm Metamorphic InAs Tunnel Injection Quantum Dot Lasers on GaAs”, Z. Mi, P. Bhattacharya and J. Yang, Appl. Phys. Lett. 89, 153109 (2006).

• “High-Speed 1.3 μm Tunnel Injection Quantum-Dot Lasers”, Z. Mi, P. Bhattacharya and S. Fathpour, Appl. Phys. Lett. 86, 153109 (2005).

Honors and awards

2006: Graduate Student Fellowship Award, IEEE/LEOS2006: Third Place Best Student Poster Award at the 2nd Nano-Optoelectronic

Workshop and BaCaTec Summer School of Advances in Photonics in Berkeley, CA, Aug. 13-18, 2006

2005: Outstanding Student Paper Award at the 23rd North American Conference on Molecular Beam Epitaxy, Santa Barbara, CA, Sep. 11-14, 2005

2005: First Place Best Student Poster Award at the 1st Nano-Optoelectronic Workshop in Berkeley, CA, Aug. 21-23, 2005

2003: University of Michigan, Rackham Graduate Fellowship1994: Pan-Deng Fellowship, Chinese Academy of Sciences


Institute of Electrical and Electronics EngineersSPIE—the International Society for Optical Engineering

Research keywords

Nanophotonics, nanomaterials, molecular beam epitaxy, quantum dot laser, nanowire photonics

Name: Michel Meunier Affiliations: Professor, Dept. of Physics Engineer-ing and program of biomedical engineering, École Polytechnique de Montréal; Canada Research Chair in Materials Micro/Nanoengineering Using Lasers; Director, Laser Processing Laboratory; Member “Groupe Polyphotonique” and “Groupe de recherche sur la science et la technologie biomédicale” Diploma: Ph.D., Materials Science, 1984, MIT, USA Email: [email protected] Web: http://lpl.phys.polymtl.ca/

Name: Zetian Mi Affiliations: Assistant professor, Department of Electrical and Computer Engineering; and Associate Member, Department of Physics, McGill University; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Applied Physics, 2006, University of Michigan, Ann Arbor, MI, USAEmail: [email protected]: http://people.mcgill.ca/zetian.mi/

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MeUNIeR M. MI Z.

Research interests

Prof. Morris’ research group specializes in time-resolved optical spectroscopy techniques. He is mainly interested in fundamental studies of quantum nanostruc-tures for applications in optoelectronic and photonic devices.

His research activities mainly aim to characterize and understand the dynamics of charge carriers and high-speed optical processes in quantum nanostructures and semiconductor microstructures. Particular attention is given to study the influence of phenomena such as optical cavity modes, intense electric and magnetic fields, the presence of traps in volume or on the surface and the relaxation and recom-bination dynamics of carriers. These studies could have a significant impact on the development of innovative devices such as photodetectors and wide bandgap electroluminescent diodes based on quantum dots, pulsed terahertz radiation detectors, bio-sensors or quantum data processing devices.

The optical and electronic properties of nano and microstructures are charac-terized using various spectroscopic tools: time-resolved photoluminescence, transitory absorption, electro-optical sampling and time-resolved terahertz spectroscopy. Theses tools allow optical measurements to be realized over the spectral range energy from the visible light to the far infrared with femtoseconde temporal resolution.


• “Electrical Characteristics and Simulation of Self-Switching-Diodes in SOI Technology”, G. Farhi, E. Saracco, J. Beerens, D. Morris, S.A. Charlebois and J. P. Raskin, Solid State Electronics 51, 1245 (2007).

• “Diluted InAs/InP(001) quantum dots grown by molecular beam epitaxy”, E. Dupuy, N. Pauc, N. Chauvin, G. Patriarche, D. Drouin, C. Bru-Chevallier, D. Morris and M. Gendry, 14th European-MBE Workshop, Granada Spain, 5-7 March, 2007.

• “Post growth engineering of InAs/GaAs quantum dots’ band-gap using proton implantation and annealing”, B. Ilahi, B. Salem, V. Aimez, L. Sfaxi, H. Maaref and D. Morris, Nanotechnology 17, 3707 (2006).

• “Toward Photocontrolled Release Using Light-Dissociable Block Copolymer Micelles”, J. Jiang, X. Tong, D. Morris and Y. Zhao, Macromolecules 39, 4633 (2006).

• “Terahertz Emission Properties of Arsenic and Oxygen Ion-Implanted GaAs Based Photoconductive Antennas”, B. Salem, D. Morris, Y. Salissou, V. Aimez, S. Charlebois, M. Chicoine and F. Schiettekatte, J. of Vac. Science and Technology A 24, 774 (2006).

Honors and awards

1994: Bourse nouveau chercheur du FCAR1991: Bourse postdoctorale du FCAR



Research keywords

Semiconductors, quantum devices, femtosecond laser, nanostructures and microstructures, optical spectroscopy

Research interests

We study the structural and dynamical properties of complex, disordered materials such as amorphous semiconductors and glasses, paracristalline semiconductors, proteins and dynamic systems. Over the courses of these studies, we have developed many new algorithms, thus making several original and important contributions both in the areas of condensed matter physics and biochemistry. The major numerical efforts needed to accomplish such work are made possible by the infrastructures of the Quebec High Performance Computing Network.

Members of the group work on the development of accelerated algorithms, such as a kinetic Monte Carlo method where the table of events is constantly updated. This allows the investigation of atomic dynamics of systems whose complexity evolves in time. We also work to understand the relationship between the network structure of glasses (such as silica or chalcogenic glasses) and their dynamic and optical properties.

We devote much effort to study the aggregation mechanisms of proteins associated, for example, with Alzheimer and Parkinson diseases. These numerical studies already led to the identification of the first stages of aggregation of small amyloidal peptides and we now work to extend our calculations to much larger systems, more experimentally relevant.


• “Self-organized criticality in the intermediate phase of rigidity percolation”, M.-A. Brière, M.V. Chubynsky and N. Mousseau, Phys. Rev. E 75, 056108 (2007).

• “Thermally-activated charge reversibility of gallium vacancies in GaAs”, Fedwa El-Mellouhi and N. Mousseau, J. Appl. Phys. 100, 083521 (2006).

• “Aggregating the amyloid Aβ(11−25) peptide into a four β -sheet structure”, Geneviève Boucher, N. Mousseau and P. Derreumaux, Proteins 65, 877 (2006).

• “Exploring the early steps of amyloid peptide aggregation by computer”, N. Mousseau and P. Derreumaux, Accounts of Chemical Research 38, 885 (2005).

• “High-quality continuous random networks”, G. T. Barkema and N. Mousseau, Phys. Rev. B 62, 4985 (2000).

Honors and awards

2006: Invited professor, Physics department, Fudan University, Shanghai, China2005: Invited scientist, Comissariat à l’énergie atomique, Saclay, France2005: Invited professor, Institute of Theoretical Physics, Universteit Utrecht,

The Netherlands2004: Canada Research Chair in Computational Physics of Complex Materials

(Tier II)


Canadian Association of Physicists (CAP)American Physical Society (APS)American Chemical Society (ACS)

Research keywords

Activation and relaxation techniques, amorphous materials, semiconductors, amyloidal proteins, protein dynamics

Name: Denis Morris Affiliations: Professor and Direc-tor, Dept. of Physics, Member, Centre de recherche en nanofabrication et nanocaractérisation (CRN2); Centre de recherche en Génie de l’Information (CEGI); Institut des Matériaux et Systèmes Intelligents (IMSI), Université de Sherbrooke; Member, Institut Canadien pour les Innova-tions en Photonique (ICIP – réseaux canadiens de centre d’excellence); Member, Advanced Laser Light Sources (ALLS – FCI) Diploma: Ph.D., Physics, 1990, Université de Montréal, Canada Email: [email protected]: www.physique.usherbrooke.ca/~dmorris/

Name: Normand MousseauAffiliations: Professor, Department of Physics, Université de Montréal; Canada Research Chair in Computational Physics of Complex Materials; Member, Réseau québécois de calcul de haute performance; Centre Robert-Cedergren en bio-informatique; Groupe d’étude des protéines membranaires Diploma: Ph.D., Physics, 1993, Michigan State University, USA Email: [email protected]: www.phys.umontreal.ca/~mousseau

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MORRIs D. MOUsseAU N.

Research interests

Our core research activities center on fast, accurate computational algorithms for simulating physical and biological phenomena. As mathematicians, our group is involved in an entire spectrum of activities, ranging from mathematical modeling in interdisciplinary environments, rigorous analysis of models, to the development of fast, accurate algorithms. We have been involved in applications arising in material science, wave propagation and electromagnetics, as well as biology. In each of these cases, we interact with experimental scientists to construct math-ematical descriptions of observed phenomena. We then build simulation tools to aid in probing these scientific principles underlying these, which in turn suggests experiments for our collaborators to test predictions from this model.


• “The nonlinear critical layer for Kelvin modes on a vortex with a continuous velocity profile”, S.A. Maslowe and N. Nigam, Siam Journal on Applied Mathematics 68, 825 (2007).

• “A multigrid algorithm for the acoustic single layer equation”, S. Gemmrich, J. Gopalakrishnan and N. Nigam, Proceedings of ENUMATH 2007, Springer (Accepted 2007).

• “Innovative Solution of a 2-D Elastic Transmission Problem”, G.C. Hsiao, N. Nigam and A.M Sandig, Applicable Analysis 86, 459 (2007).

• “Error Analysis of an Enhanced DtN--FE Method for Exterior Scattering Problems”, D.P. Nicholls and N. Nigam, Numerische Mathematik 105, 267 (2006).

• “Mechanism of Psychoactive Drug Action in the Brain: Simulation Modeling of GABAA Receptor Interactions at Non-Equilibrium”, S. Qazi. M. Caberlin and N. Nigam, Current Pharamaceutical Design 13, 1437 (2007).

Honors and awards

2007: NSERC Discovery Accelerator Supplement2005: Principal’s Prize for Excellence in Teaching, McGill University1999: Industrial Postdoctoral Fellowship, Institute for Mathematics and its

Applications, University of Minnesota


Canadian Mathematics SocietyCanadian Applied and Industrial Mathematics SocietySociety for Industrial and Applied MathematicsAssociation for Women in Mathematics

Research keywords

Numerical and applied analysis, high-performance computing, interdisciplinary modeling, electromagnetics, material science

Research interests

Our research activities aim to develop tunable optical micro and nano systems for a wide range of applications (astronomy, telecommunications, biology, aeronau-tics, space, biomedical, etc...)

We design, fabricate and characterize optical micro and nano systems. Optical MicroElectro Mechanical Systems (OMEMS) are multidisciplinary by essence. Their optical, electrostatic, mechanical design is based on analytical analysis and numerical simulations. The fabrication is based on micro and nano machining of silicon, using thin film layer deposition as well as dry (plasma) and wet etching. Nanofabrication of photonic crystals coupled with mobile MEMS devices, open the path to novel tunable nanophotonic devices.

Recently, we fabricated advanced deformable micromirrors for exoplanets observation.

We develop new tunable optical filters, based on silicon photonic crystals, for telecommunications applications. Photonic crystals are also being used in our research laboratory for navigation systems in space. Tunable two-dimensional photonic crystals are investigated for enhanced multianalyte detection in bio-chemistry.

We are also developing specific micro sensors for structure health monitoring of aircrafts. Finally, we investigate novel optical microcavities for extremely sensitive bio-chemical sensors.


• “Single-Crystal-Silicon Continuous Membrane Deformable Mirror Array for Adaptive Optics in Space-based Telescopes”, I. W. Jung, Y.-A. Peter, E. Carr, J.-S. Wang and O. Solgaard, IEEE J. Select. Topics Quantum Electron 13, 162 (2007).

• “Deformable MEMS grating for wide tunability and high operating speed”, M. Tormen, Y.-A. Peter et al., Journal of Optics A: Pure and Applied Optics 8, S337 (2006).

• “Photonic crystal slabs demonstrating strong broadband suppression of trans-mission in the presence of disorders”, O. Kilic, S. Kim, W. Suh, Y.-A. Peter et al., Opt. Lett. 29, 2782 (2004).

• “Micro-optical fiber switch for a large number of interconnects using a deformable mirror”, Y.-A. Peter et al., IEEE Photon. Technol. Lett. 14, 301 (2002).

• “Pulsed fiber laser using micro-electro-mechanical (MEM) mirrors”, Y.-A. Peter et al., Opt. Eng. 38, 636 (1999).


Institute of Electrical and Electronics Engineers (IEEE/LEOS)Optical Society of America (OSA)Swiss Physical SocietySPIE

Research keywords

MEMS, NEMS, microfabrication, nanotechnology, nanophotonics

Name: Nilima NigamAffiliations: Assistant Professor, Department of Mathematics and Statistics, McGill University; Member, Centre de Recherches Mathématiques, Montréal; Associate Member, Mathematical Analysis Laboratory and Applied Mathematics Laboratory, CRM; Since 2008: Simon Fraser University, Burnaby, B.C. CanadaDiploma: Ph.D., Applied Mathematics, 1999, University of Delaware, USAEmail: [email protected]: www.math.sfu.ca/~nigam/

Name: Yves-Alain Peter Affiliations: Professor, Engineering Physics and Scientific Director, Microfabrication Laboratory and Founding member, Groupe Poly Photonique, École Polytechnique de Montréal; Member, Regroupement Stratégique en Microsystèmes du Québec (ReSMiQ)Diploma: Dr.Sc., 2001, University of Neuchâtel, SwitzerlandEmail: [email protected]: www.polymtl.ca/mems/en/

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NIGAM N. PeTeR y.-A.

Research interests

We are interested in the magnetism and superconductivity of strongly correlated systems. The materials under study are mainly uni- or bi-directional organic conductors and magnetic insulators of the RMnO3 type. Their elastic, magnetic and electronic properties are studied by two experimental techniques, adapted particularly well to such systems: ultrasonic propagation, speed and attenuation, between 30 and 500 MHz, and ultra high frequency absorption between 9 and 60 GHz. Experimental equipment include a cryostat equipped with a supercon-ductive 18 Tesla magnet, a VTI (variable temperature insert) for temperatures between 2-300 K and a 0,02-2 K dilution refrigerator. Moreover, cells using a liquid or a gas (helium) give us the possibility to make ultrasounds measurements under hydrostatic pressure of up to 12 Kbar.

Our principal interest is to characterize the phase diagram of 1D organic conduc-tors of the (TMTSF)2X type and of 2D organic conductors of the κ-(BEDT-TTF)2X type, in order to identify the symmetry of the order parameter of the superconduc-tor and to specify the zone of coexistence with magnetism.


• “Competition between magnetism and superconductivity in the organic metal κ-(BEDT-TTF)2Cu[N(CN)2]Br”, D. Fournier, M. Poirier and K.D. Truong, Phys. Rev. B 76, 054509 (2007).

• “Raman study of κ-ET2Cu[N(CN)2]Cl at ambient and ~ 300 bars pressures”, K.D. Truong, S. Jandl and M. Poirier, Synthetic Metals 157, 252 (2007).

• “First Order Phase Transition in the Frustrated Antiferromagnet CsNiCl3”, G. Quirion, X. Han, M.L. Plumer and M. Poirier, Pys. Rev. Lett. 97, 077202 (2006)

• “Impact of the reduction process o0n the long-range antiferromagnetism in Nd1.85Ce0.15CuO4”, P. Richard, M. Poirier, S. Jandl and P. Fournier, Phys. Rev. B 72, 184514 (2005).

• “Landau model for the elastic properties of the quasi-one-dimensional antiferromagnetic compound CsNiCl3”, G. Quirion, T. Taylor and M. Poirier, Phys. Rev. B 72, 094403 (2005).

Honors and awards

1983: Chercheur Boursier Universitaire CRSNG, Département de Physique, Université de Sherbrooke

1977: NSERC postdoctoral scholarship, Laboratoire de Spectrométrie Physique, Université Scientifique et Médicale de Grenoble


American Physics Society

Research keywords

Superconductivity, magnetism, organics, ultrasonics, microwaves

Research interests

We study and develop numerical tools to characterize the fundamental properties (quantum size effects, quantum charge transport and electronic structure) of nanomaterials (quantum dots, molecular wires, organometallic nanostructure) which are mostly electroactive organic materials.

We develop two different computational tools. The first one, a software called SPAGS-STM (Strongly Parallel Adaptive Grid Solvers – STM), is part of a new generation of tools devoted to real-time STM imaging. Current efforts of the group aim to extend the real-time feature to very large-scale model, and to evaluate the tunnel current very accurately. In addition, intrusive STM imaging in which one can perform structural deformations and chemical modifications of the studied materials is under development. In a second software, we develop a hybrid method, integrating both Kinetic Monte-Carlo simulation and Level Set technique, meant to tackle very large scale atomistic simulations of nanostructure growth.

Our group also participates in applied studied, investigating electroactive organic materials for organic electronics, photovoltaics and catalysis. The variation of electronic structure and electron transport as a function of the molecular organization in the materials, and the stability, reactivity and structure of new nanostructure and supramolecular systems, are among the properties studied.


• “Nanoscale Adaptive Meshing for Rapid STM Imaging”, S.Bedwani, F. Guibault and A. Rochefort, Journal of Computational Physics 227, 6720 (2008).

• “Tailoring Electronic and Charge Transport Properties of Molecular π-Stacked Heterojunctions”, A. Rochefort and P. Boyer, Applied Physics Letters 89, 092115 (2006).

• “On the Control of Carbon Nanostructures for Hydrogen Storage Applications”, P. Guay, B. Stansfield and A. Rochefort, Carbon 42, 2187 (2004).

• “Electronic and Transport Properties of Carbon Nanotube Peapods”, A. Rochefort, Physical Review B 67, 115401 (2003).

• “Electrical Switching in π-Resonant 1D Intermolecular Channels”, A. Rochefort, R. Martel and Ph. Avouris, Nano Letters 2, 877 (2002).

Honors and awards

1999: ACFAS Concours de vulgarisation scientifique


Ordre des ingénieurs du QuébecAmerican Physics SocietyAmerican Chemical Society

Research keywords

Electroactive materials, organic nanostructure, computational STM imaging, hybrid numerical methods

Name: Mario Poirier Affiliation: Professor, Department of Physics, Université de SherbrookeDiploma: Ph.D., Physics, 1978, Université de Montréal, CanadaEmail: [email protected]: www.physique.usherb.ca

Name: Alain Rochefort Affiliation: Professor, Department of Engineering Physics, École Polytechnique de Montréal Diploma: Ph.D., Petroleum Sciences – Chemistry, 1992, Université Pierre et Marie Curie, FranceEmail: [email protected]: http://nanostructures.phys.polymtl.ca

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POIRIeR M. ROChefORT A.

Research Interests

Sjoerd Roorda uses MeV ion beams to modify and characterize materials. “Modify” can be ion implantation (adding impurities such as electrical or optical dopants), ion irradiation (to introduce defects or to make a crystal amorphous altogether) or ion beam deformation (irradiation with multi-MeV ions which can lead to macroscopic deformation of spherical particles).

In the case of amorphous materials, ion beams can be used to make very pure and reproducible samples of amorphous semiconductors, which can then be studied by, e.g., x-ray diffraction, Raman scattering, or calorimetry. Similarly, controlled amounts of point defects can be introduced into semiconductor crystals and the annealing behaviour studied by a combination of infrared absorption spectroscopy, positron annihilation, and differential scanning calorimetry.

Gold nanoparticles, embedded in silica and deformed by irradiation with swift heavy ions, exhibit a surface plasmon resonance induced absorption band that is tunable and polarization dependent. The atomic mechanism leading to the elongation of the –initially spherical– nanoparticles is not known and a subject of interest since it would inform us about the basic response of materials to ion irradiation.

Medical applications of ion beam modification include ion implantation of stents (for coronary arteries) and coils (to treat cerebral aneurysms) with (radioactive) phosphourous-32. The P-32 is a pure beta-emitter, which affects the growth of cells in the immediate vicinity of the stent or the coil once it is implanted into the patient.


• “Deformation, alignment and anisotropic optical properties of gold nanoparticles embedded in silica”, C. Harkati, J.M. Lamarre, L. Martinu and S. Roorda, Nucl. Instr. and Meth. B 257, 24 (2007).

• “Ion-implantation and characterization of P-32-radioactive platinum coils for endovascular treatment of intracranial aneurysms”, P. Leblanc, J. Raymond and S. Roorda, Nucl. Instr. and Meth. B 242, 173 (2006).

• “Divacancies in proton irradiated silicon: Comparison of annealing mechanisms studied with infrared spectroscopy and positron annihilation”, R. Poirier, V. Avalos, S. Dannefaer, F. Schiettekatte and S. Roorda, Nucl. Instr. and Meth. B 206, 85 (2003).

• “High-energy X-ray diffraction study of pure amorphous silicon”, K. Laaziri, S. Kycia, S. Roorda, M. Chicoine, J.L. Robertson, J. Wang and S.C. Moss, Phys. Rev. B 60, 13520 (1999).


Canadian Association of Physicists (CAP)American Physics Society (APS)Kaiserlich Konigsliche Böhmische Physikalische Gesellschaft

Research keywords

Ion beam modification of materials, amorphous materials, crystal defects, semiconductors, nanoparticles

Research interests

I apply a variety of nuclear techniques to problems in magnetism.

I have broadened my repertoire from conventional 57Fe Mössbauer spectroscopy, to include neutrons (diffraction, depolarisation, and polarised reflectometry), μ SR, 119Sn Mössbauer, low temperature conversion electron Mössbauer spectroscopy (LT-CEMS) and selective excitation double Mössbauer (SEDM). I have also developed the capability to prepare and use a variety of higher energy cold-source Mössbauer transitions, with 197Au, 170Yb and 166Er now firmly established.

We have combined SEDM and μ SR to investigate the nature of the magnetic fluc-tuations in the vicinity of Txy and obtain a direct, quantitative cross-check of the fluctuation rates derived from our analysis. This work is complemented by state of the art numerical calculations made using the Centre’s Beowulf computing cluster.

We led the establishment of sub-Kelvin powder diffraction capability at the Canadian Neutron Beam Centre (CNBC) at Chalk River and my students and I have used the system in two major projects ( Er3Cu4X4 (X = Si, Ge, Sn) and Yb5SixGe4-x ) and collaborated with an Italian group to study a molecular nanomagnet system (“Fe-17”) to obtain the first direct evidence of long-ranged magnetic order in these new materials.

We are currently adding a sub-Kelvin Mössbauer facility to my lab.


• “Low background single crystal silicon sample holders for neutronpowder diffraction”, M. Potter, H. Fritzsche, D.H. Ryan and L.M.D. Cranswick, J. Appl. Cryst. 40, 489 (2007).

• “Anisotropic contributions to the 119Sn transferred hyperfine fields in RMn6Sn6-xXx (R=Y,Tb,Er; X=In,Ga)”, L.K. Perry, D.H. Ryan and G. Venturini, Phys. Rev. B 75, 144417 (2007).

• “Phase diagrams of site frustrated Heisenberg models on simple cubic, bcc and fcc lattices”, A.D. Beath and D.H. Ryan, Phys. Rev. B 73, 214445 (2006).

• “Valence and magnetic ordering in the Yb5SixGe4-x pseudobinary system”, C.J. Voyer, D.H. Ryan, K. Ahn, K.A. Gschneidner, Jr. and V.K. Pecharsky, Phys. Rev. B 73, 174422 (2006).

• “Magnetic fluctuations in Eu2BaNi1-xZnxO5 Haldane systems”, J. van Lierop, C.J. Voyer, T.N. Shendruk, D.H. Ryan, J.M. Cadogan and L. Cranswick, Phys. Rev. B 73, 174407 (2006).



Research keywords

Magnetism, Mössbauer spectroscopy, neutron diffraction, frustration, molecular magnets

Name: Sjoerd Roorda Affiliations: Professor, Department of Physics, and Director, Ion beam laboratory, Université de Montréal; Director, Thin Film Physics and Technology Research Center; CE Member, RQMP Diploma: Ph.D., Physics, 1990, Utrecht University, The NetherlandsEmail: [email protected]

Name: Dominic RyanAffiliations: Professor, Department of Physics, McGill University; President of the Canadian nstitute for Neutron ScatteringDiploma: Ph.D., Experimental Physics, 1986, Dublin University, IrelandEmail: [email protected]: www.physics.mcgill.ca/~dominic/

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ROORDA s. RyAN D.

Research interests

Sacher’s group is interested in the chemistry and physics of surfaces and interfa-ces, especially as they relate to structural modifications and interfacial interactions leading to the increased adhesion of deposited metals. The group uses surface analysis techniques found in the LASM, as well as in other cooperating laboratories to study the nature of the bonding controlling adhesion. Our recent studies include:

1. the demonstration that the Doniach-Sunjic theory of photoemission asymmetry does not hold for transition metal nanoparticles; these results have been used to understand the adhesion of Pt nanoparticles to various carbon-containing substrates, for use in fuel cells;

2. the controlled functionalization of various carbon-containing substrates; these results have been used in increasing the active loading of various transition metal nanoparticles above what was previously attained;

3. the functionalization of magnetic nanoparticles; these results are being used to aid in targeted drug delivery in the human body.


• “X-Ray Photoelectron Spectroscopic Analysis of Pt Nanoparticles on Highly Oriented Pyrolytic Graphite, Using Symmetric Component Line Shapes”, G.-X. Zhang, D.-Q. Yang and E. Sacher, J. Phys. Chem. C 111, 515 (2007).

• “XPS Demonstration of π-π Interaction Between Benzyl Mercaptan and Multiwalled Carbon Nanotubes, and Their Use in the Adhesion of Platinum Nanoparticles”, D.-Q. Yang, B. Hennequin and E. Sacher, Chem. Mater. 18, 5033 (2006).

• “Evidence of the Interaction of Evaporated Pt Nanoparticles with Variously Treated Surfaces of Highly Oriented Pyrolytic Graphite”, D.-Q. Yang, G.-X. Zhang, E. Sacher, M. José-Yacamàn and N. Elizondo, J. Phys. Chem. B 110, 8348 (2006).

• “Room Temperature Air Oxidation of Nanostructured Si Thin Films with Varying Porosities, as Studied by X-Ray Photoelectron Spectroscopy”, D.-Q. Yang, M. Meunier and E. Sacher, J. Appl. Phys. 99, 84315 (2006).

• “Platinum Nanoparticle Interaction with Chemically Modified Highly Oriented Pyrolytic Graphite Surfaces”, D.-Q. Yang and E. Sacher, Chem. Mater. 18, 1181 (2006).

Honors and awards

2002: Editor, Conference Proceedings, Workshop on Polymer Metallization, “Polymer Metallization II”, Kluwer, New York

2001: Chairman, Workshop on Polymer Metallization, Montréal, June 27-29.1998: Invited Lecturer, course on Surface Analysis, Department of Materials

Engineering, Technion, Israel1998: Wenger Fund Award for study in Israel1997: Fellow, IEEE1996: Co-chairman, colloque “Surfaces et Interfaces des Matériaux Avancés”

of the Neuvième Entretiens Jacques-Cartier, Montréal, October 2-41992: Fellow, Royal Society of Chemistry, London1991: Editor, Conference Proceedings, International Symposium on the

Metallization of Polymers: ACS Symposium Series, volume 4401989: Chairman, International Symposium on the Metallization of Polymers,

Montreal, September 24-28 (Sponsored by the American Chemical Society)1985: Prix d’excellence de l’École Polytechnique1982, 1983: Two AUCC Horizon-le-Monde fellowships for study in Europe1981: Chairman of the Executive Committee of the IEEE Conference on Electrical

Insulation and Dielectric Phenomena

Research keywords

Surface analysis and reactions, biocompatibility, interfacial interactions, surface modifications, nanoscience

Research interests

Our activities are in the field of electroactive materials engineering for applica-tions in organic electronics and photoelectrochemistry.

We fabricate organic semiconducting films based on molecules and polymers as functional components of field-effect transistors, electroluminescent diodes and transistors, and sensors.

To understand physical processes such as charge carrier injection and transport, we study the film forming process since the early stages of the growth and we accurately select the device structure, which provides for the experimental configuration to characterize the films. The device is then a “tool” to investigate the films - to understand its underlying physics we investigate films structure at metal/semiconductor, dielectric/semiconductor interfaces. Scanning probe and diffraction techniques are usually employed together with optical (fluorescence) techniques.

By “soft” deposition methods such as sol-gel or electrodeposition we prepare nanostructured, transparent films of metal oxide semiconductors. Films are ap-plied as photoelectrodes for photoelectrohemical and photocatalytic applications, namely hydrogen production from water photoelectrolysis and photodegradation of organic pollutants. We investigate films micro- and nano-structural features, such as mesoporosity and particle shapes, sizes, and connectivity as they dra-matically influence their photoactivity.


• “Organic Light Emitting Field Effect transistors: Advances and Perspectives”, F. Cicoira and C. Santato, Advanced Functional Materials (Review) 17, 3421 (2007).

• “Synthesis and characterization of polycrystalline Sn and SnO2 films with wire morphologies”, C. Santato, C. M. Lopez and K.-S. Choi, Electrochemistry Communications 9, 1519 (2007).

• “Correlation between morphology and field-effect transistor mobility in tetracene thin films”, F. Cicoira, C. Santato, F. Dinelli, M. Murgia, M. A. Loi, F. Biscarini, R. Zamboni, P. Heremans and M. Muccini, Advanced Functional Materials 15, 375 (2005).

• “Tetracene light-emitting transistors on flexible plastic substrates”, C. Santato, I. Manunza, A. Bonfiglio, F. Cicoira, P.Cosseddu, R. Zamboni and M. Muccini, Applied Physics Letters 86, 141106 (2005).

• “Crystallographically oriented mesoporous WO3 films: synthesis, characterization and applications”, C. Santato, M. Ulmann, M. Odziemkowski and J. Augustynski, Journal of the American Chemical Society 123, 10639 (2001).

Honors and awards

2006: Canadian Bureau for International Education Fellowship, INRS-EMT, Varennes

2001: Swiss National Science Foundation Post-Doc Fellowship, University of Geneva

1995: Erasmus Scholarship, University of Bologna


American Chemical SocietyAmerican Physics SocietyMaterials Research SocietyPan-American Pigment Cell Society

Research keywords

Nanoscience, organic electronics, photoelectrochemistry, solar energy conversion

Name: Edward SacherAffiliations: Researcher, Department of Engineering Physics, École Polytechnique de Montréal; Associate Director/Founder: Laboratory for the Analysis of the Surfaces of Materials (LASM), the Montreal regional surface laboratoryDiploma: Ph.D., Physical Chemistry, 1960, the Pennsylvania State University, USAEmail: [email protected]: www.polymtl.ca/recherche/rc/en/ professeurs/details.php?NoProf=147

Name: Clara Santato Affiliations: Assistant Professor, Department of Engineering Physics, École Polytechnique de Montréal; Research Scientist at Italian National Research Council (ISMN-Bologna)Diploma: Ph.D., Chemistry, 2001, University of Geneva, SwitzerlandEmail: [email protected]

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sACheR e. sANTATO C.

Research interests

Based in the Ion Beam Lab of the Université de Montréal, François Schiettekatte and his team use ion implantation to synthesize and modify nanostructures. They have a special interest in understanding the evolution of implantation-induced damage, and use it, for example, to modify quantum structures.

For its investigations, the team namely developed and continues to improve nano-calorimetry. This technique makes possible the measurement of the heat involved in a reaction or process with sensitivity of the order of a nanojoule. The technique is applied to the measurement of the heat released by low-energy-ion implanta-tion damage annealing and solid-state reactions in thin films.

Using the accelerator facility, the team also provides ion beam analysis services and expertise to the nano-science community. Techniques like Rutherford Backscattering Spectrometry and Elastic Recoil Detection allow quantitative depth profiling of elements in materials with a depth resolution better than 10 nm.


• “Damage evolution in low-energy-ion implanted silicon”, R. Karmouch, Y. Anahory, J.-F. Mercure, D. Bouilly, M. Chicoine, G. Bentoumi, R. Leonelli, Y.Q. Wang and F. Schiettekatte, Phys. Rev. B 75, 075304 (2007).

• “Drastic ion-implantation-induced intermixing during annealing of self-assembled InAs/InP(001) quantum dots”, C. Dion, P. Desjardins, M. Chicoine, F. Schiettekatte, P.J. Poole and S. Raymond, Nanotechnology 18, 015404 (2007).

• “Structural relaxation of amorphous silicon depends on implantation tempera-ture”, J.-F. Mercure, R. Karmouch, Y. Anahory, S. Roorda and F. Schiettekatte, Phys. Rev. B 71, 134205 (2005).

• “Faceting of Si Nanocrystals Embedded in SiO2”, Y.Q. Wang, R. Smirani, F. Schiettekatte and G.G. Ross, Chem. Phys. Lett. 409, 129 (2005).

• “Discrete Periodic Melting Point Observations for Nanostructures Ensembles”, M.Yu. Efremov, F. Schiettekatte, M. Zhang, E.A. Olson, A. T. Kwan, R.S. Berry and L.H. Allen, Phys. Rev. Lett. 85, 3560 (2000).

Honors and awards

1998: Canada’s Governor General’s Academic Medal (Ph.D.) 1998: Prix d’excellence académique du Directeur Général de l’INRS (Ph.D.)



Research keywords

Nanoscience, nanocalorimetry, ion implantation, defects, ion beam analysis

Research Intrests

High-temperature superconductors, organic superconductors and colossal magneto-resistance materials are characterized by important residual interac-tions between electrons. This makes their study very complicated when using the conventional theoretical methods of Solid State Physics. Theoretical models, such as the Hubbard model, which takes into account a screened (on site) Coulomb repulsion in addition to the usual band kinetic energy, are used to describe these systems but their properties are very complex to calculate.

Prof Sénéchal’s group puts in much effort in the development and application of quantum cluster methods. These aim to approximate the solution of the Hubbard model on an infinite lattice by the exact solution on a cluster of small size (for example 16 atoms or less) of a slightly different model, defined in order to optimize its correspondence with the exact model on an infinite lattice. These methods describe well the pseudogap phenomenon in high-temperature super-conductors, as well as the proximity of antiferromagnetic and superconductive phases in the same materials. They are also applied to organic superconductors and other materials with strong electronic correlations.


• “Antiferromagnetism and Superconductivity in Layered Organic Conductors: Variational Cluster Approac”, P. Sahebsara and D. Sénéchal, Phys. Rev. Lett. 97, 257004 (2006).

• “Pseudogap and high-temperature superconductivity from weak to strong coupling. Toward quantitative theory”, A.-M.S. Tremblay, B. Kyung and D. Sénéchal, Fizika Nizkikh Temperatur (Low Temperature Physics) 32, 561 (2006).

• “Competition between Antiferromagnetism and Superconductivity in High-Tc Cuprates”, D. Sénéchal, P.-L. Lavertu, M.-A. Marois and A.-M.S. Tremblay, Phys. Rev. Lett. 94, 156404 (2005).

• “Hot Spots and Pseudogaps for Hole- and Electron-Doped High-Temperature Superconductors”, D. Sénéchal and A.-M.S. Tremblay, Phys. Rev. Lett. 92, 126401 (2004).



Research keywords

Quantum materials, Hubbard’s model, superconductivity numerical methods, strongly correlated electrons

Name: François SchiettekatteAffiliation: Professor, Department of Physics, Université de MontréalDiploma: Ph.D., Sciences of energy and materials, 1997, INRS-CanadaEmail: [email protected]: www.lps.umontreal.ca/~schiette

Name: David Sénéchal Affiliations: Professor, Department of Physics, Université de Sherbrooke; Director, Réseau qué-bécois de calcul de haute performance (RQCHP); National Initiatives Committtee Compute/Calcul CanadaDiploma: Ph.D., Physics, 1990, Cornell University, USAEmail: [email protected]: www.physique.usherbrooke.ca/senechal

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sChIeTTeKATTe f. séNéChAL D.

Research interests

Organic semiconductor materials are now widely applied in optoelectronic devices such as field-effect transistors, light-emitting diodes and photovoltaic diodes. The nature of electronic interactions between molecules determines the bulk electronic properties in these new materials. A natural strategy to achieve three-dimensional control of intermolecular interactions is to exploit molecular self assembly in solution prior to the casting process by means of supramolecular forces. With this approach, molecular building blocks are self-assembled to form well-defined, complex architectures through non-covalent bonds, such as Coulombic, and van der Waals interactions. With this approach, high carrier mobilities, for example, can be achieved.

The central theme of our programme is to understand and exploit the electronic processes in self-organising semiconductor nanostructures constructed with π-conjugated materials. Our focus is on excited-state dynamics in functional supramolecular assemblies with tailored intermolecular electronic interactions. We combine optical spectroscopies and electrical measurements in device architectures to unravel electronic dynamics, making direct links between phe-nomena important in devices and molecular length-scale phenomena, spanning timescales from femtoseconds to milliseconds. The programme seeks a scope of general understanding of the interdependence of hierarchical structure of organic architectures and electronic function in supramolecular electronics.


• “Role of Intermolecular Coupling in the Photophysics of Disordered Organic Semiconductors: Aggregate Emission in Regioregular Polythiophene”, J. Clark, C. Silva, R.H. Friend and F.C. Spano, Phys. Rev. Lett. 98, 206406 (2007).

• “Supramolecular Electronic Coupling in Chiral Oligothiophene Nanostructures”, S. Westenhoff, A. Abrusci, W.J. Feast, O. Henze, A.F.M. Kilbinger, A.P.H.J. Schenning and C. Silva, Advanced Materials 18, 1281 (2006).

• “Influence of Copolymer Interface Orientation on the Optical Emission of Poly-meric Semiconductor Heterojunctions”, P. Sreearunothai, A.C. Morteani, I. Avilov, J. Cornil, D. Beljonne, R.H. Friend, R.T. Phillips, C. Silva and L.M. Herz, Phys. Rev. Lett. 96, 117403 (2006).

• “Electric Field-Induced Transition from Heterojunction to Bulk Charge Recombination in Bilayer Polymer Light-emitting Diodes”, A.C. Morteani, P.K.H. Ho, R.H. Friend and C. Silva, Appl. Phys. Lett. 86, 163501 (2005).

• “Exciton Regeneration at Polymeric Semiconductor Heterojunctions”, A.C. Morteani, P. Sreearunothai, L.M. Herz, R.H. Friend and C. Silva, Phys. Rev. Lett. 92, 247402 (2004).

Honors and awards

2005: Canada Research Chair in Supramolecular Optoelectronics (Tier II)2001: Advanced Research Fellowship, EPSRC, UK2001: Nonstipendiary Research Fellowship, Darwin College, Cambridge1997: Overend Award for Outstanding Graduate Research in Physical Chemistry,

University of Minnesota1996: Graduate School Doctoral Dissertation Fellowship, University of Minnesota1994: John Wertz Award for Outstanding Graduate Research in Chemical Physics,

University of Minnesota1992: Fulbright Graduate Fellowship


American Physical Society (APS)American Chemical Society (ACS)

Research keywords

Organic optoelectronics, exciton and polaron dynamics, ultrafast spectroscopy, light-emitting diodes, photovoltaic cells

Research interest

The Siwick Research Group conducts interdisciplinary research focused on atomic-level studies of structural dynamics in molecules and materials. The laboratory is based on two primary experimental research tools; ultrafast electron diffraction (UED) and multi-wavelength ultrafast spectroscopy.

UED is a technique that combines ultra-short pulse lasers with home-built elec-tron microscopes to measure the atomic structure of matter with time-resolution below 10-12 s (the timescale at which chemical bonds are made or broken and the associated atomic displacements occur). We are developing an entirely new electron source for such experiments that promises to remove most of the current limitations on the technique. With this source it will soon be possible to make atomic-level ‘movies’ of chemical reactions and material phase transitions, providing essentially the equivalent of a molecular-dynamics simulation in the laboratory.

We also study chemical reaction dynamics using ultrafast laser spectroscopy. In particular, we use time-resolved visible and mid-IR spectroscopies to study aqueous inter and intra molecular proton-transfer in a variety of systems. These are one of the most fundamental classes of chemical reaction and the dynamics are highly complex, since the solvent water molecules play an active (and often determining) role.


• “On the Role of Water in Intermolecular Proton Transfer Reactions”, B. J. Siwick and H. J. Bakker, in “Ultrafast Phenomena XV”, Springer Series in Chemical Physics 88, P. Corkum, D. Jonas, R. J. D.

Miller and A. M. Weinder eds. (Springer-Verlag, New York, 2007).

• “Ultrafast Electron Microscopy in Material Science, Biology and Chemistry”, W. E. King, G. H. Campbell, A. M. Frank, B. W. Reed, J. Schmerge, B. J. Siwick, B. C. Stuart and P. M. Weber, J. Appl. Phys. 97, 111101 (2005).

• “Characterization of Ultrashort Electron Pulses by Electron-Laser Pulse Cross-Correlation”, B. J. Siwick, A. A. Green, C. T. Hebeisen and R. J. D. Miller, Opt. Lett. 30, 1057 (2005).

• “Femtosecond Electron Diffraction Studies of Strongly Driven Structural Phase Transitions”, B. J. Siwick, J. R. Dwyer, R. E. Jordan and R. J. D. Miller, Chem. Phys. 299, 285 (2004).

• “An Atomic-Level View of Melting Using Femtosecond Electron Diffraction”, B. J. Siwick, J. R. Dwyer, R. E. Jordan and R. J. D. Miller, Science 302, 1382 (2003- cover story of the Nov. 21, 2003 issue).

Honors and awards

2006: Canada Research Chair in Ultrafast Science (Tier II)2005: Natural Science and Engineering Research Council of Canada

Doctoral Prize2004: NSERC post-doctoral fellowship1998: NSERC post-graduate fellowship


Canadian Association of Physicists (CAP)American Physical Society (APS)American Chemical Society (ACS)

Research keywords

Ultrafast electron diffraction, ultrafast laser spectroscopy, femtochemistry, reaction dynamics, phase transitions

Name: Carlos Silva Affiliations: Assistant Professor, Department of Physics, Université de Montréal; Canada Research Chair in Supramolecular OptoelectronicsDiploma: Ph.D., Chemical Physics, 1998, University of Minnesota, USAEmail: [email protected]: www.phys.umontreal.ca/~silva/

Name: Bradley Siwick Affiliations: Assistant Professor, Departments of Physics and Chemistry, McGill University; Canada Research Chair in Ultrafast ScienceDiploma: Ph.D., Physics, 2004, University of Toronto, CanadaEmail: [email protected]: www.physics.mcgill.ca/~siwick/

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sILVA C. sIwICK b.

Research interests

My research concentrates on the time evolution of microstructures formed under non-equilibrium conditions and is heavily based on the use of x-ray diffraction techniques. Microstructures are central to the physical and mechanical properties of most materials. Not only failure rates, but many other important properties in-cluding tensile strength, chemical reactivity and magnetic coercivity, depend cru-cially on this morphology. The typical length scales of these structures is microns or smaller. Many of the advanced materials often denoted as “modern space age” materials get their properties from tailoring their microstructure by careful and sophisticated processing techniques. Furthermore, it is an important fundamental problem in physics to understand both how such microstructures arise and how to characterize them. Disordered and non-equilibrium systems span the range of materials including binary alloys (Ni3Al used for jet turbines), directionally solidified crystals (snowflakes) and soft-condensed matter systems (rubber). The nature of coherence and correlations in these systems is still not fully understood. I use real-time in-situ x-ray diffraction, microdiffraction and intensity fluctuation spectroscopy (mostly at the Advanced Photon Source), to measure time-evolution of the microstructure under conditions similar to those used in processing.


• “X-Ray Intensity Fluctuation Spectroscopy Studies on Phase-Ordering Systems”, A. Fluerasu, M. Sutton and E.M. Dufresne, Phys. Rev. Lett. 94, 055501 (2005).

• “X-ray intensity fluctuation spectroscopy by heterodyne detection”, F. Livet, F. Bley, F. Ehrburger-Dolle, I. Morfin, E. Geissler and M. Sutton, J. Synchrotron Rad. 13, 453 (2006).

• “Microstructure of Ferroelectric Domains in BaTiO3 Observed via X-Ray Microdiffraction”, M.V. Holt, Kh Hassani and M. Sutton, Phys. Rev. Lett. 95, 085504 (2005).

• “Aging in a filled polymer: Coherent small angle x-ray and light scattering”, E. Geissler, A-M. Hecht, C. Rochas, F. Bley, F. Livet and M. Sutton, Phys. Rev. E 62, 8308 (2000).

• “Using direct illumination CCDs as high-resolution area detectors for x-ray scattering”, F. Livet, F. Bley, J. Mainville, R. Caudron, S. G. J. Mochrie, E. Geissler, G. Dolino, D. Abernathy, G. Grübel and M. Sutton, Nucl. Inst. and Meth. A 451, 596 (2000).

Honors and awards

2005: Ernest Rutherford Professor of Physics; McGill University2004: W.C. Macdonald Professor of Physics, McGill University2001: Brockhouse Medal, Canadian Association of Physics1999: Killam Fellowship, Canada Council of the Arts



Research keywords

X-ray diffraction, materials science, correlation spectroscopy, non-equilibrium statistical mechanics, nanoscience

Research interests

Szkopek’s research group develops semiconductor nanostructures for electronics and photonics applications. Taking advantage of semiconductor fabrication tech-niques and emerging device concepts, Szkopek’s group is addressing fundamen-tal issues in security, remote sensing and telecommunications.

We are developing a new class of photodetectors: ultra-high gain photoconductors based on the integration of single quantum dots with nanoscale transistors. This new class of detectors has a wide array of potential applications, from extending the range of quantum cryptographic networks to superior imaging arrays in the far-IR / THz band. We are optimizing device material and structure to achieve the best possible detector sensitivity, with the aim of bridging the wide gap between current detector performance and fundamental physical limits imposed by the laws of quantum mechanics and electromagnetism. In related work, we are studying the focusing of radiation to deep sub-wavelength volumes using plas-mon / polariton resonances, with the aim of improving detector performance.

We also investigate new electronic materials. With the recent discovery of the field-effect in graphene — a monolayer of carbon atoms — there has been much interest in the fundamental properties of electron transport in graphene. Our laboratory is studying the potential application of graphene to transistors with ultra-high gain-bandwidth product and low noise. This work involves understand-ing the nature and origin of electronic defects in graphene devices. Successful development of graphene transistors will find application to high speed / low noise amplification in telecommunications.


• “Multiple-multipole simulation of optical nearfields in discrete metal nanosphere assmblies”, W.-Y. Chien and T. Szkopek, Opt. Express 16, 1820 (2008).

• “Plasmonic interconnects versus conventional interconnects: a comparison of latency, crosstalk and energy costs”, J.A. Conway, S. Sahni and T. Szkopek, Opt. Express 15, 4474 (2007).

• “Threshold error penalty for fault tolerant computation with nearest neighbour communication”, T. Szkopek, P.O. Boykin, H. Fan, V. Roychowdhury, E. Yablonovitch, G. Simms, M. Gyure and B. Fong, IEEE Trans. Nanotech. 5, 42 (2006).

• “Single photo-electron trapping, storage, and detection in a one-electron quantum dot”, D.S. Rao, T. Szkopek, H.D. Robinson, E. Yablonovitch and H.W. Jiang, J. Appl. Phys. 98, 114507 (2005).

• “Novel multimode fiber for narrow-band Bragg gratings”, T. Szkopek, V. Pasupathy, J.E. Sipe and P.W.E. Smith, IEEE. J. Sel. Top. Quantum Electron. 7, 425 (2001).


American Physics Society

Research keywords

Nanoelectronics, nanophotonics, nanofabrication, optoelectronics, quantum information

Name: Mark SuttonAffiliation: Professor, Department of Physics, McGill UniversityDiploma: Ph.D., Physics, 1981, University of Toronto, CanadaEmail: [email protected]: www.physics.mcgill.ca/~mark

Name: Thomas Szkopek Affiliations: Professor, Department of Electrical and Computer Engineering, and Associate Member, Department of Physics, McGill University; Member, Institut Transdisciplinaire d’Informatique Quantique (INTRIQ)Diploma: Ph.D., Electrical Engineering, 2006, University of California Los Angeles, USAEmail: thomas.szkopek@ mcgill.caWeb: www.ece.mcgill.ca/~ts7kop/

sUTTON M. sZKOPeK T.

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Research interestsThe Taillefer Research Group probes electron behaviour in novel materials. In certain materials, electrons collaborate to produce magnetism and superconductivity, states of matter whose properties have been harnessed in applications such as high-density storage using giant-magnetoresistance devices and magnetic resonance imaging using superconducting magnets.

As electron interactions get stronger, the possibility for unexpected behaviour and even new states of matter grows substantially. The Taillefer group studies this by cooling materials down to extremely low temperatures and subjecting them to very strong magnetic fields, looking at how they transport charge and heat.

A particularly dramatic surprise was the discovery of high-temperature superconduc-tivity in a class of oxide materials known as cuprates in 1986. The mystery is how these materials can be transformed from an insulator to the best-known superconduc-tor by removing some electrons. Cuprates seem to defy the theory of Fermi liquids — one of the cornerstones of condensed matter physics. More than 100,000 research pa-pers have addressed the cuprate phenomenon, but no consensus has been achieved.

One of the major research thrusts in the Taillefer group is to establish whether Fermi-liquid theory does indeed break down in cuprates and understand why they are such good superconductors.

Selected publications• “Bulk evidence for single-gap s-wave superconductivity in the intercalated

graphite superconductor C6Yb”, M. Sutherland, N. Doiron-Leyraud, L. Taillefer, T. Weller, M. Ellerby and S.S. Saxena,

Phys. Rev. Lett. 98, 067003 (2007).• “Onset of a boson mode at the superconducting critical point of underdoped

YBa2Cu3Oy”, N. Doiron-Leyraud, M. Sutherland, S.Y. Li, Louis Taillefer, R. Liang, D.A. Bonn and W.N. Hardy,

Phys. Rev. Lett. 97, 207001 (2006).• “High-temperature superconductivity: Electrons scatter as they pair”, L. Taillefer, Nature Physics 2, 810 (2006).• “Non-vanishing energy scales at the quantum critical point of CeCoIn5”,

J. Paglione, M.A. Tanatar, D.G. Hawthorn, R.W. Hill, F. Ronning, M. Sutherland, L. Taillefer and C. Petrovic,

Phys. Rev. Lett. 97, 106606 (2006).• “Thermal conductivity in the vicinity of the quantum critical endpoint in

Sr3Ru2O7”, F. Ronning, R.W. Hill, M. Sutherland, D.G. Hawthorn, M.A. Tanatar, J. Paglione, L. Taillefer, M.J. Graf, R.S. Perry, Y. Maeno and A.P. Mackenzie,

Phys. Rev. Lett. 97, 067005 (2006).

Honors and awards2008: Lifetime achievement award (Canadian Association of Physicists) 2007, 2003: Top Ten Discoveries of the Year, magazine Québec Science2007: Fellow of the Royal Society of Canada2003: Prix Marie-Victorin (Québec Government)2003: Brockhouse medal (Canadian Association of Physicists)2003: Fellow of the American Physical Society2002: Scientist of the Year, Radio-Canada (French radio; Les Années-Lumière)2002: Canada Research Chair in quantum materials (Tier I)1998: E.W.R. Steacie Memorial Fellowship (NSERC)1998: Herzberg Medal (Canadian Association of Physicists)1998: Prix Urgel-Archambault (ACFAS)1993: Research Fellowship, Alfred P. Sloan Foundation

Professional affiliationsCanadian Association of Physicists (CAP)American Physical Society (APS)Association francophone pour le savoir (AFCAS)American Association for the Advancement of Sciences (AAAS)

Research keywordsQuantum materials, superconductivity, quantum phase transitions, ultra-low temperatures

Research interests

We seek to better understand the quantum mechanics of metal oxides or, more generally, systems containing d or f electrons. Their fascinating properties like superconductivity at high temperature, giant magneto-resistance and new states of matter, are promises of many applications in modern electronics. However, the study of their properties poses a fundamental theoretical challenge. They have in common: a) a very strong anisotropy (one or two-dimensional), b) important collective quantum phenomena, and c) the presence of such strong interactions between electrons that they lead to paramagnetic insulating phases (Mott insula-tors). These materials are called quantum materials. We use many-body theory methods (Green functions, functional derivatives…) and numerical simulations using the most powerful computer clusters in Canada, to develop new theories, aiming to generalize the theory of solids described in textbooks. What is the origin of superconductivity at high temperature? How can the collective modes destroy the Fermi surface? How can interactions lead to situations where a system exhib-its both insulating and metallic behavior at the same time? These are examples of the theoretical and experimental questions that motivate the research program of this Chair.


• “Comment on “Spin Correlations in the Paramagnetic Phase and Ring Exchange in La2CuO4”, L. Raymond, G. Albinet and A.-M. S. Tremblay, Phys. Rev. Lett. 97, 049701 (2006).

• “Mott Transition, Antiferromagnetism, and d-wave Superconductivity in Two-Dimensional Organic Conductors”, B. Kyung and A.-M. S. Tremblay, Phys. Rev. Lett. 97, 046402 (2006).

• “Pseudogap and high-temperature superconductivity from weak to strong coupling. Toward quantitative theory”, A.-M. S. Tremblay, B. Kyung and D. Sénéchal, Low Temperature Physics (Fizika Nizkikh Temperatur) 32, 561 (2006).

• “Competition between Antiferromagnetism and Superconductivity in High Tc cuprates”, D. Sénéchal, P.-L. Lavertu, M.-A. Marois and A.-M. S. Tremblay, Phys. Rev. Lett. 94, 156404 (2005).

• “Pseudogap and Spin Fluctuations in the Normal State of Electron-Doped Cuprates”, B. Kyung, V. Hankevych, A.-M. Daré and A.-M. S. Tremblay, Phys. Rev. Lett. 93, 147004 (2004).

Honors and awards

2004: Fellow of the Canadian Academy of the Sciences and Humanities (FRSC)2003: Prix Urgel-Archambault, ACFAS 2001: Canada Research Chair in Theoretical Physics (Tier I)1991-1999: Director, Centre de recherches en physique du solide,

Université de Sherbrooke2001: CAP-CRM Prize in Theoretical and Mathematical Physics, 2001 1992: Killam Fellowship, Arts Council1988: Member of the Canadian Institute of Advanced Research1987: Steacie Fellowship from NSERC1986: Herzberg Medal, Canadian Association of Physicists


Association canadienne des physiciens (ACP)American Physical Society (APS)

Research keywords

Correlated electrons, high-temperature superconductivity, quantum cluster approaches to correlated materials, many-body problem in transition metal oxides and optical lattices

Name: Louis TailleferAffiliations: Professor, Department of Physics, Université de Sherbrooke; Canada Research Chair in Quantum Materials; Director, Quantum Materials program, Canadian Institute for Advanced Research (CIFAR)Diploma: Ph.D., Physics, 1986, University of Cambridge, UKEmail: [email protected]: www.physique.usherbrooke.ca/taillefer

Name: André-Marie TremblayAffiliations: M.S.R.C., Professor, Department of Physics, Université de Sherbrooke; Canada Research Chair in Theoretical Physics; Member, Quantum Materials program, Canadian Institute for Advanced Research (CIFAR)Diploma: Ph.D., Physics, 1978, MIT, Boston, USAEmail: [email protected]: www.physique.usherbrooke.ca/tremblay

TAILLefeR L. TReMbLAy A.-M.

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Research interests

Our research is of theoretical and computational nature, and focuses on non-equilibrium phenomena in extended systems, and in applications of Statistical Mechanics to problems in Biophysics or Biomaterials. In the former case, we aim at understanding the mechanisms underlying the formation and evolution of spatio temporal patterns in systems driven outside of thermodynamic equilibrium, including the transition to spatio temporal chaos in extended systems. We focus on prototypical systems and related experimental configurations in which to address fundamental issues of nonlinear phenomena, as well as on configurations of interest because of their applications in soft matter, materials science, and engineering. In the latter case, we are developing a coarse grained description of biomolecules, including reduced models of a protein that can provide high throughput and moderate resolution models of its structure, extending this description to include solvent mediated interactions, and applying them to ongoing protein engineering efforts.


• “Grain boundary dynamics in stripe phases of non potential systems”, Z.-F. Huang and J. Viñals, Phys. Rev. E 75, 056202 (2007).

• “Stability of parallel/perpendicular domain boundaries in lamellar block copolymers under oscillatory shear”, Z.-F. Huang and J. Viñals, J. Rheol. 51, 99 (2007).

• “Unified framework for dislocation-based defect energetics”, J.M. Rickman, J. Viñals and R. LeSar, Phil. Mag. A 85, 917 (2005).

• “A phenomenological model of weakly damped Faraday waves and the associated mean flow”, J.M. Vega, S. Ruediger and J. Viñals, Phys. Rev. E 70, 046306 (2004).

Awards

Canada Research Chair in Nonequilibrium Materials (Tier I)

Research keywords

Nonlinear dynamics, pattern formation, nonequilibrium phenomena

Research interests

Professor Wertheimer’s research group is primarily active in the study of “cold” plasmas, both under partial vacuum and at atmospheric pressure. The research has objectives not only to better understand this “fourth state of matter” through diagnostics (e.g. using optical emission spectroscopy) and theoretical modeling, but to use plasma processing for applications in advanced materials science. An important example of the latter is plasma-enhanced chemical vapor deposition (PECVD) of high-performance thin films for modern electronics and photonics.

Most recently, the emphasis has been in the area of bio-medical materials, in particular, plasma-functionalized polymers or thin “plasma-polymer” films as substrates for the controlled growth of living cells. These (mostly nitrogen-rich) materials are proving to be useful in orthopedic and vascular medical devices, for example as cell-adhesive surfaces on stent-grafts, as well as for fundamental studies in cell-biology. A very promising example of the latter is the observation that gene-expression of mesenchymal stem cells (MSC) grown on amine-rich surfaces can be influenced by the substrates’ particular chemical structure.


• “Nitrogen-Rich Coatings for Promoting Healing Around Stent Grafts for Endovascular Aneurysm Repair”, S. Lerouge, A. Major, P.-L. Girard-Lauriault, M.-A. Raymond, P. Laplante, G. Soulez, F. Mwale, M.R. Wertheimer and M.-J. Hébert, Biomaterials 28, 1209 (2007).

• “Suppression of Genes Related to Hypertrophy and Osteogenesis in Committed Human Mesenchymal Stem Cells Cultured on Novel Nitrogen-rich Plasma Polymer Coatings”, F. Mwale, P.-L. Girard-Lauriault, H.T. Wang, S. Lerouge, J. Antoniou and M.R. Wertheimer, Tissue Engineering 12, 2649 (2006).

• “Spectroscopic Diagnostics of Atmospheric Pressure Helium Dielectric Barrier Discharges in Divergent Fields”, V. Poenariu, M.R. Wertheimer and R. Bartnikas, Plasma Processes and Polymers 3, 17 (2006).

• “Plasma-Enhanced Chemical Vapour Deposition (PECVD) of Nanocrystalline Silicon Layers on High-Tg Polymer Substrates”, L.A. MacQueen, J. Zikovsky, G. Dennler, M. Latrèche, G. Czeremuszkin and M.R. Wertheimer, Plasma Processes and Polymers 3, 58 (2006).

• “A New Encapsulation Solution for Flexible Organic Solar Cells”, G. Dennler, C. Lungenschmied, H. Neugebauer, N.S. Sariciftci, M. Latrèche, G. Czeremuszkin and M.R. Wertheimer, Thin Solid Films 511-512, 349 (2006).

Honors and awards

2006: named Professor Emeritus, École Polytechnique de Montréal1996: NSERC Industrial Research Chairholder1990: Killam Research Fellow, The Canada Council1986: IEEE Fellow


Institute of Electrical and Electronics Engineers (IEEE)American Physical Society (APS)Order of Engineers of Quebec (OIQ)

Research keywords

Plasma science, thin films, surfaces and interfaces, biomaterials

Name: Jorge ViñalsAffiliations: Professor, Department of Physics, McGill University; Canada Research Chair in Nonequilibrium Materials; Diploma: Ph.D., Physics, 1983, University of Barcelona, SpainEmail: [email protected]: www.physics.mcgill.ca/~vinals/

Name: Michael R. WertheimerAffiliations: Professor Emeritus, Department of Engineering Physics, École Polytechnique de Montréal; Co-Editor-in-Chief, Plasma Processes and Polymers, Wiley-VCH, Weinheim, GermanyDiploma: Ph.D., Physics, 1967, Université de Grenoble, FranceEmail: [email protected]: www.polymtl.ca/recherche/rc/ professeurs/details.php?NoProf=150&showtab=REC

VINALs j. weRTheIMeR M.R.

Research Interests

My research interests lie at the interface between the physical and biological sciences. I am interested in understanding the molecular mechanisms involved in cellular adhesion (how biological cells stick together and to an underlying substrate) and how cells dynamically regulate adhesion receptors to control cellular migration. I approach these problems by using fluorescence microscopy imaging methods and fluctuation/correlation analysis of the images (so-called image correlation techniques). The image correlation microscopy allows us to measure transport properties and interactions of proteins in living cells and neu-rons and generate vector maps of directed transport in cells. I am also interested in developing new biophysical methods such as third harmonic generation (THG) microscopy and the use of bioconjugated quantum dots as robust luminescent labels for biophysical imaging applications on live cells and neurons. Other pro-jects will make use of an atomic force microscope (AFM)/total internal reflection fluorescence (TIRF) microscope that was built in collaboration with Prof. P. Grütter in Physics at McGill.


• “Detection and correction of blinking bias in image correlation transport measurements of quantum dot tagged macromolecules”, N. Durisic, A. I. Bachir, D. L. Kolin, B. Hebert, B. C. Lagerholm, P. Grutter and P. W. Wiseman, Biophysical Journal 93, 1338 (2007).

• “Probing the integrin-actin linkage using high resolution protein velocity mapping”. C. M. Brown, B. Hebert, D. L. Kolin, J. Zareno, L. Whitmore, A. R. Horwitz and P. W. Wiseman, Journal of Cell Science 119, 5204 (2006).

• “k-Space image correlation spectroscopy (kICS): A method for accurate transport measurements independent of fluorophore photophysics”, D. L. Kolin, D. Ronis and P. W. Wiseman, Biophysical Journal 91, 3061 (2006).

• “Characterization of Blinking Dynamics in Quantum Dot Ensembles using Image Correlation Spectroscopy”, A. Bachir, N. Durisic, B. Hebert, P. Grutter and P. W. Wiseman, Journal of Applied Physics 99, 064503 (2006).

• “Spatio temporal image correlation spectroscopy (STICS): Theory, verification and application to protein velocity mapping in living CHO cells”, B. Hebert, S. Costantino and P. W. Wiseman, Biophysical Journal 88, 3601 (2005).

Honors and awards

2007: Leo Yaffe Award for Excellence in Teaching McGill University2007: NSERC Accelerator Grant Awardee2005: Biophysical Society Young Fluorescence Investigator Research Award


Biophysical SocietySPIE

Research keywords

Biophysics, biophysical chemistry, quantum dots, image correlation methods, nonlinear microscopy

Research interests

My activities are based on an interest in the behaviour of thin films and surfaces. They have usually involved magnetic materials, especially ferromagnetic resonance (FMR) studies of these. In 1994, we began investigations of the giant magnetoimpedance (GMI) effect. We found that amorphous magnetic metallic microwires produced in Montreal were ideal for these studies, and for sensor applications. We developed models for this effect, based on the earlier work on FMR. We are using the same approach for the investigation of non-linear effects and of noise in GMI, comparing theoretical and experimental results.

To investigate the static behaviour of nanowire arrays of the same materials, we have used the method of first order reversal curve (FORC) diagrams, and have also contributed to the advancement of the FORC methodology. The high frequency behaviour of the nanowire arrays, understood as metamaterials, is of interest for microwave applications.

Our work on structural instabilities in a-Si:H, and on the modelling of carrier time-of flight in this material has continued. This led us to an interest in activated processes, and in the Meyer-Neldel rule. We postulated the multi-excitation entropy mechanism as the origin of the rule, and developed its implications. We are considered to be the leading experts in this field.


• “Reversible and quasireversible information in first-order reversal curve dia-grams”, F. Béron, L. Clime, M. Ciureanu, D. Ménard, R.W. Cochrane and A. Yelon, J. Appl. Phys. 101, 09J107 (2007).

• “Second harmonic of nonlinear magnetoimpedance in amorphous magnetic wires with helical anisotropy”, D. Seddaoui, D. Ménard, P. Ciureanu and A. Yelon, J. Appl. Phys. 101, 0903907 (2007).

• “Multi-excitation entropy: its role in thermodynamics and kinetics”, A. Yelon, B. Movaghar and R.S. Crandall, Rep. Prog. Phys. 69, 1145 (2006).

• “Magnetostatic interactions in dense nanowire arrays”, L. Clime, P. Ciureanu and A. Yelon, J. Magnetism Magnet. Mater. 297, 60 (2006).

• “Surface plasmons in Drude metals”, A. Yelon, K.N. Piyakis and E. Sacher, Surf. Sci. 569, 47 (2004).

Honors and awards

Emeritus Professor, École Polytechnique de MontréalLife Fellow, Institute of Electrical and Electronic Engineers (IEEE)

Professional affliations

Canadian Association of PhysicistsAmerican Physical SocietyInstitute of Electrical and Electronic EngineersMaterials Research SocietyAmericam Vacuum SocietyAmerican Association of Physics TeachersElectrochemical Society

Research keywords

Magnetism, microwires and nanowires, multiexcitation entropy, surfaces, sensors

Name: Paul W. WisemanAffiliations: Associate Professor, Department of Physics and Department of Chemistry, McGill University; Associate Member, CRCN (Centre de recherche sur le cerveau, le comportement et la neuropsychiatrie), Université LavalDiploma: Ph.D., Chemistry, 1995, University of Western Ontario, CanadaEmail: [email protected]: http://wiseman-group.mcgill.ca/

Name: Arthur Yelon Affiliation: Emeritus professor, Department of Physics Engineering, École Polytechnique de MontréalDiploma: Ph.D., Physics, 1961, Case Institute of Technology, USAEmail: [email protected]

46 | RQMP | MeMbeRs

wIseMAN P.w. yeLON A.

research projects Nanostructure materials electronics and photonics48 Electronic dynamics in supramolecular semiconductors 49 Characterization of the electronic and the dielectric properties of advanced materials using terahertz spectroscopy50 Laser-induced bandgap engineering of III-V quantum semiconductors 51 Understanding fully characterized molecular systems: A combined Scanning Tunneling Microscopy,

Atomic Force Microscopy and Field Ion Microscopy study of molecules at surfaces52 Constructing a single molecule device: Foundations and future 53 Non-volatile memory based on single electron trap

Magnetism in materials and systems54 Magnetocaloric materials: Theory and experiment 55 Ferromagnetic nanowire arrays for high frequency devices

Quantum properties of materials56 Electron and skyrmion crystals in graphene 57 Quantum optics and quantum information processing with superconducting circuits 58 Theory of quantum electromechanical systems 59 Resistively detected NMR in quantum hall states 60 Investigation into the optical manipulation and resistive readout of the GaAs nuclear spins 61 Elastic properties of quasi-1D and -2D organic superconductors 62 Cooperative emission study in ytterbium doped Y2SiO5

63 Superconductivity, antiferromagnetism and new phases of matter in correlated materials64 Vortex dynamics and novel superconductors 65 Nanoscale electronic structure of strongly correlated electron systems 66 Disorder in two-dimensional electron systems67 Exploration of the Fermi surface in high-Tc cuprate superconductors68 Quantum semiconductor biosensor69 Role of Fermi surface reconstruction in high-temperature superconductors 70 Exciton thermal escape in self-assembled quantum dots 71 Electronic structure of single quantum dots investigated by electrostatic force microscopy at 4.5 K 72 Ultra low temperature scanning probe microscope

Advanced characterization and fabrication of novel materials73 Controlling metal nanoparticle dispersion on carbon nanotubes through understanding their interfacial interactions74 Femtosecond electron diffraction: Making atomic-level movies of molecules and materials75 Structure of amorphous silicon — defects, local order and relaxation76 Visco-elastic properties of rubber 77 Laser based “green” synthesis of non-toxic nanoparticles for biomedical applications78 High lumen/watt blue and UV light emitting diodes based on AlGaN/GaN heterostructures

using inductively coupled plasma etching79 AFM for the life sciences: Neurons, smooth muscle cells and blinking q-dots 80 Micromechanical biochemical sensors 81 Pattern formation outside of equilibrium82 Ink-paper interaction for papers with high mineral content

Technological properties of materials83 Silicides and germanides for next generation electronic circuits:

Novel reaction pathways and crystalline texture evolution84 Doppler imaging with optical coherence tomography: Medical and microfluidic applications 85 Micro-accelerometer for structural health monitoring of aircrafts 86 Advanced erosion and tribo-corrosion resistant coatings87 Nano-structured optical interference coatings88 Interface engineering of materials for biomedical applications

48 | RQMP | PRojects | nanostRuctuRes MateRials electRonics and Photonics

We seek a detailed microscopic picture of electronic dynamics in supramolecular semiconductor nanostructures by implementing time-resolved spectroscopies with femtosecond time resolution and spanning many decades in time.

Electronic dynamics in supramolecular semiconductors

Researcher: Carlos SilvaCollaborator: Albert Schenning (Technical University Eindhoven)Students: Jean-François Glowe and Françoise ProvencherContact: Carlos Silva; [email protected]; www.phys.umontreal.ca/~silva/

In supramolecular electronics, complex architectures are built with molecular ‘bricks’, and these structures are designed to have electronic properties that can be used as active components in electronic applications. This enables fabrication of displays, solar cells, and other electronic devices with materials that are essentially plastics. Useful applications of these organic semiconductors depend upon the controlled interactions between molecules, and benefit from well-defined intermolecular structure. For example, the efficiency of charge transport is enhanced when molecules adopt ordered conformations with molecular interactions in a direction parallel to the transport direction. Our objectives are to measure, in real time, processes that are important in electronic applications of these nanostructures. Understand-ing electronic processes in these new and exciting materials is essential for further development of organic electronics beyond incremental optimisation of materials and device parameters. However, the understanding obtained from this programme will have profound implications for other areas of science. For example, we will develop comparisons with light harvesting in photosynthesis and charge transport in DNA. Furthermore, this research is timely because of recent development of model materials to correlate unambiguously structure with electronic dynamics. This work takes advan-tage of the synergistic efforts of chemists and physicists to design new materials for electronic applications.

The scientific issues in this programme are attacked with spectroscopic methodologies, complimented with electri-cal measurement. The justification for the spectroscopic approach is two-fold. Firstly, optical spectroscopy allows for “electrodeless” probing of electronic processes. Secondly, there is no other means to interrogate electronic dynam-ics occurring on all relevant timescales directly in the time domain. We make connections between electronic dynam-ics when we place nanostructures between electrodes (occurring on microsecond timescales and beyond) and those important at molecular length scales (occurring in picosecond timescales or faster). The combined application gives complementary information on kinetics of absorptive and luminescent transient species over timescales span-ning femtoseconds to milliseconds.

A functionalised sexithophene derivative ( n = 6 ) that forms chiral supramolecular stacks. The relative PL intensity is plotted as a function of time. The decay fits to an exponential function ( t = 5 ns ) at early times (blue curve) and to a stretched exponential function ( t = 77 ns, b = 0.5) at later times (red curve).

Femtosecond transient absorption dynamics of molecular crystals of EPPTC-perylene, whose molecular structure is shown in the inset. The pump pulse wave-length is 490 nm, while that of the probe is 630 nm. The probe is polarised either parallel (red curve) or perpendicular (black curve) relative to the pump. Also shown in the inset is an optical micrograph of the perylene film placed between crossed polarisers demonstrating the crystalline microstrucure.

References

• “Role of Intermolecular Coupling in the Photophysics of Disordered Organic Semiconductors: Aggregate Emission in Regioregular Polythiophene”, J. Clark, C. Silva, R.H. Friend and F.C. Spano, Phys. Rev. Lett. 98, 206406 (2007).

• “Supramolecular Electronic Coupling in Chiral Oligothiophene Nanostructures”, S. Westenhoff, A. Abrusci, W.J. Feast, O. Henze, A.F.M. Kilbinger, A.P.H.J. Schenning and C. Silva, Adv. Mater. 18, 1281 (2006).

• “Exciton Regeneration at Polymeric Semiconductor Heterojunctions”, A.C. Morteani, P. Sreearunothai, L.M. Herz, R.H. Friend and C. Silva, Phys. Rev. Lett. 92, 247402 (2004).

49 | RQMP | PRojects

Antenna-type devices made on photoconductive materials has been fabricated for the emission and the detection of pulsed terahertz radiation. These devices are used to build a time-domain terahertz spectroscopy setup. The terahertz traces show a very good signal to noise ratio of about a thousand and this experimental setup gives access to a large bandwidth extending from 0.1 up to 4 THz. High-frequency dielectric properties measurements of polymeric films have already been obtained using this setup. Other studies of time-resolved electronic properties of quantum materials are presently conducted within our RQMP group. These fundamental studies are important and the development of innovative terahertz devices with improved characteristics.

Researchers: Denis Morris, Daniel Houde, Serge Charlebois, Patrick Fournier, Vincent Aimez, François Schiettekatte, Carlos Silva, Richard Martel and Martin ChicoineCollaborators: Alain Cornet and Isabelle Huynen (UCL-Belgique); S. Dodge (Simon-Fraser); Tobias Hertel (U. Vanderbilt, Nashville, TN USA)Students: Jean-François Allard, Stéphane Savard, Françoise Provencher and François MeunierContact: Denis Morris; [email protected]; www.physique.usherbrooke.ca/morris/

A schematic of the time-domain terahertz spectroscopy setup is shown in Figure 1. The principle of this technique consists in measuring, in the temporal domain, the ampli-tude of the THz wave packet transmitted through a test sample. The spectrum of this THz temporal trace is then obtained using a numerical Fourier transform. This spec-trum can be compared with the one obtained for a reference sample (or with no sample). The complex ratio of these THz amplitude spectra are used to extract the dielectric proper-ties of the sample. This technique finds several applications in domains such as hyper frequency device electronics, pharmacology and biomedical.

Time-resolved photoconductivity of different materials of interests for optoelectronics can also be studied using a similar setup with an extra visible pump beam. A second delay line has to be used in order to control the arriving time of the optical pump pulses on the sample. This visible-pump THz-probe technique can be used for fundamental studies of the electronic properties of advanced materials, such as high-Tc superconductors, semiconductor nano-structures, organic polymers and carbon nanotubes. All this materials are presently been fabricated within the RQMP

infrastructure and are the object of intensive research activities. A better understanding of the electronic proper-ties of these materials is essential for the development of innovative photonic and electronic devices. Our interests are particularly focused on the improvement of the THz emitter characteristics as well as the realization of active filters and waveguides in the THz regime. These devices are fabricated within our major central facilities (financed by Nano-Québec). Our THz research activities also include collaborations with academic researchers from Canada, Belgium, and United States of America. The national defense R&D center at Val-Cartier and the Institut National d’Optique at Québec are active participants in some of our THz research projects and both organizations are highly interested in the valorization of their output results.

References

• “Terahertz Emission Properties of Arsenic and Oxygen Ion-Implanted GaAs Based Photoconductive Antennas”, B. Salem, D. Morris, Y. Salissou, V. Aimez, S. Charlebois, M. Chicoine and F. Schiettekatte, J. of Vac. Science and Technology A 24, 774 (2006).

• “Ultrafast Dynamics of Delocalized and Localized Electrons in Carbon Nanotubes”, L. Perfetti, T. Kampfrath, F. Schapper, A. Hagen, T. Hertel, C.M. Aguirre, P. Desjardins, R. Martel, C. Frischkorn and M. Wolf, Phys. Rev. Lett. 96, 027401 (2006).

• “High-frequency dielectric properties measurements of polymeric films using time-domain terahertz spectroscopy”, J.F. Allard et al., Thirteenth Canadian Semiconductor Conference – CSTC, Montreal, August 14-17 (2007).

Figure 1. Time-domain THz spectroscopy

Characterization of the electronic and the dielectric properties of advanced materials using terahertz spectroscopy


The objective of this research is to investigate both fundamental and applied aspects of laser-based processes of quantum well and quantum dot intermixing that have the potential to lead to cost-attractive fabrication of advanced photonic devices or monolithically integrated photonic circuits that otherwise would have not been attainable with conventional micro-/nanofabrication methods.

Researchers: Jan J. Dubowski, Vincent Aimez and Richard Arès Collaborators: Robin Williams and Zbig Wasilewski (IMS-NRC Canada) Students: Alex Voznyy, Jonathan Genest, Radoslaw Stanowski and Romain BealContact: Jan J. Dubowski; [email protected]; www.gel.usherbrooke.ca/crn2/pages_personnel/dubowski/accueil_en.htm

Selective area bandgap engineering of quantum semicon-ductor heterostructures is the subject of intense investiga-tion due to the potential of this approach in the fabrica-tion of advanced devices and photonic integrated circuits (PICs). The challenge is to develop an innovative manu-facturing technology capable of cost-attractive delivery of PICs. For quantum well (QW) and quantum dot (QD) micro-structures, spatially selective intermixing of the QW (QD) and barrier material, known as quantum well (dot) intermix-ing (QWI/QDI), has been investigated as a feasible route to this end. The selective area intermixing and tuning of the QD emission wavelength is of particular interested due to the attractive perspective of applications of QDs as photon emitters, detectors and solar cells.

Lasers are highly attractive for the post-growth processing technologies due to the ease with which they can modify surface properties or temperature of wafers in selected sites. The success of such an approach will depend on the prog-ress of our understanding of the fundamental phenomena governing the laser-matter interaction. At the UdeS Labora-tory for Quantum Semiconductors and Laser-based Nano-technology, we investigate QW/QD intermixing phenomena using UV excimer lasers (UV-QWI) and an IR Laser-RTA (rap-id thermal annealing) technique. Figure 1 shows an example of an InGaAs/InGaAsP QW sample that following selective area irradiation with a 193 nm excimer laser was annealed at 725°C for 120 sec. Blue-shifts in excess of 100 nm can easily be achieved for such QW microstructures.

Figure 2 shows a series of emission spectra obtained from a monolithically integrated multiwavelength laser chip fabri-cated with the Laser-RTA technique. A modeling study has indicated that the Laser-RTA technique has the potential to provide significant blue shifts with micrometer-size spa-tial resolution. Thus, this one-step post-growth process-ing approach is particularly attractive for tuning emission wavelength of individual QDs or their ensembles grown on nano-patterned substrates. The Laser-RTA technique is investigated with a variety of CW laser sources (405, 473, 532, 980, 1064 and 10600 nm) which, depending on a studied QW/QD heterostructure, are used individually or in tandems.

The 405 nm CW laser used in this study has been provided by the RQMP funds.

References

• “Suppressed intermixing in InAlGaAs/AlGaAs/GaAs and AlGaAs/GaAs quantum well heterostructures irradiated with a KrF excimer laser”, J. Genest, J.J. Dubowski and V. Aimez, Appl. Phys. A 89, 423 (2007).

• “Multibandgap quantum well wafers by IR laser quantum well intermixing: simulation of the lateral resolution of the process”, O. Voznyy, R. Stanowski and J.J. Dubowski, J. Laser Micro/Nanoengineering 1, 48 (2006).

• “Laser-induced selective area tuning of GaAs/AlGaAs quantum well microstructures for two color IR detector operation”, J.J. Dubowski, C.Y. Song, J. Lefebvre, Z. Wasilewski, G. Ares and H.C. Liu, J. Vac. Sci. Tech. A 22, 887 (2004).

Figure 2. Emission spectra from a monolithically integrated (2 mm long) multi-wavelength semiconductor laser chip obtained with the Laser-RTA technique.

Figure 1. Photoluminescence map of an InGaAs/InGaAsP QW sample with an array of sites emitting at different wavelengths obtained with the UV-QWI technique [J. Genest, PhD thesis].

Laser-induced bandgap engineering of III-V quantum semiconductors


This project focuses on three main subjects — Contact formation at the atomic level, Nano indentation and the deeper understanding of Scanning Tunneling Microscope/Atomic Force Microscope (STM/AFM) contrast mechanisms.

Researchers: Peter Grütter, Yoichi Miahara and Hong GuoCollaborators: U. Dürig (IBM); W. Hofer (Liverpool); G. Cross (Trinity College); A. Schirmeisen (Muenster) Students: Mehdi El Ouali and Till HagedornContact: Peter Grütter; [email protected]; www.physics.mcgill.ca/spm

In order to study atomically characterized systems, we use a homebuilt instrument combining a Scanning Tunnel-ing Microscope (STM), an Atomic Force Microscopy (AFM) and a Field Ion Microscope (FIM). This allows us to study the mechanical and electronic interactions of atomically defined systems.

In a recent publication [1] we show how to use FIM to image and reconstruct the atomic tip structure. Figure 1 shows a sequence of FIM images. The bright spots in the center of the image are individual tungsten atoms. We can also modi-fy the tip structure in a controlled way with this technique by applying suitable voltage pulses. We can thus machine a tip atom by atom! Using such a tip one can also characterize the sample surface on an atomic scale using STM or AFM.

The main focus of our current research is Molecular Elec-tronics. Molecular electronics is a promising new field of Physics where quantum transport phenomena in individual molecules can be observed, measured and used. Under-standing quantum transport effects in nanostructures and molecules is both invaluable to fundamental science and of critical importance to modern information technology. The ongoing trend of electronic device miniaturization will soon lead to devices with transport characteristics that are dominated by quantum effects. From a fundamental pers-pective there is a severe lack of experimental techniques that can make measurements of electron transport in molecular systems with accurate knowledge of the atomic details. Currently available experimental techniques, such as break junctions, provide little insight into crucial details of the system such as bonding positions and molecular orien tation — even the number of atoms in a break junction is not controlled. Theoretical calculations have demonstra-ted that transport characteristics are often dominated by details of the contacts. Our experiments allow a critical, no fit parameter test of theoretical models. Figure 2 shows the formation of a contact between a three atom tip and a gold (111) surface. We simultaneously measure forces as well as

current as a function of separation between the tip and the sample. On the top horizontal axis we see the separation between STM tip and sample. We go from a separation of 16 angstrom to contact, press 2 angstrom in and retract the tip afterwards. This cycle is repeated several times. The current (in blue) and the force (in red) show us how the con-tact forms [2].

Investigating the onset of indentation and the formation of dislocations in metals is traditionally done by Nano indenta-tion. Our three atom tip is the smallest and best defined nano indenter possible [3]. By pressing it in a controlled fashion into an atomically flat sample many questions in that field can be addressed. Will the behaviour at the atomic scale be similar to the macroscopic experiments. Are there phenom-ena not seen in modelling due to size or time constraints?

References

[1] “Determination of the atomic structure of scanning probe microscopy tungsten tips by field ion microscopy”, A.A. Lucier, H. Mortensen, Y. Sun and P. Grutter, Phys. Rev. B 72, 235420 (2005).

[2] “From tunneling to point contact: Correlation between forces and current”, Y. Sun, H. Mortensen, S. Schar, A.S. Lucier, Y. Miyahara and P. Grutter, Phys. Rev. B 71, 193407 (2005).

[3] “Plasticity, healing and shakedown in sharp-asperity nanoindentation”, G.L.W. Cross, A. Schirmeisen, P. Grutter and U.T. Durig, Nature Materials 7, 370 (2006).

Figure 1. Field Ion Microscopy give us structural information about the STM tip as well as the opportunity to engineer the tip structure.

Figure 2. Simultaneous current and force measurement during tip-sample approach and retraction cycles.

Understanding fully characterized molecular systems: A combined Scanning Tunneling Microscopy, Atomic Force Microscopy and Field Ion Microscopy study of molecules at surfaces


The advancement of molecular electronics depends upon an improved understanding of electronic transport mechanisms through single molecules. In order to compare to existing theoretical models, atomically well defined devices are needed as the effect of local structure is known to be significant. We aim to construct such a device in a planar geometry on an insulator to be characterized by high resolution noncontact AFM.

Researchers: Peter Grütter and Hong GuoCollaborators: R. Hoffmann (U. Karlsruhe); R. Möller (U. Duisburg-Essen); E. Shoubridge (Montreal Neurological Institute); M. Elliott (U. Cardiff); M. Jericho (U. Dalhousie)Students: S. Burke, S. Fostner, J. Topple and J. Mativetsky (Graduated in 2006)Contact: Peter Grütter; [email protected]; www.physics.mcgill.ca/spm

In the field of molecular electronics, where single molecules are utilized as the active components of an electronic device, it is commonly acknowledged that the electrodes and envi-ronment play a role in the properties of the device as well as the molecule. Due to this sensitivity to the local structure one must know the atomic scale structure of the device region, including the electrodes and substrate, in order to compare reliably with theoretical predictions of the transport proper-ties. It is the central goal of this project to construct and characterize a single molecule device in order to advance understanding of molecular transport mechanisms.

The approach we will take is to build a planar device, such that it can be characterized by scanning probe microscopy techniques and in the ultra-clean environment of UHV to eliminate unknown contaminants. We will also use an insu-lating surface, so that electronic transport can be measured without current bypass through the substrate. In order to construct such a device, a basic knowledge of growth pro-cesses and interactions of both molecules and metals on insulators must first be understood.

Using the non-contact atomic force microscope (nc-AFM), we have made considerable progress on understanding growth of molecules and metals on ionic surfaces. With this technique we are able to determine the molecular structure of organic deposits on alkali halides and elucidate important processes in growth. In order to control the growth, we have explored templating of the surface by creation of monatomic depth nanopits which trap molecules, as well as pre-seeding with metal deposits to initiate nucleation. Through a com-bination of these techniques we have proposed a strategy for creating a device structure on the nanoscale with well defined metal clusters acting as the final contact. To create contacts from the mm scale down to the nanoscale in UHV, metal deposition through a shadow mask system is under development. Metal growth studies have allowed us to determine the best selections of metals to use for elec-trode patterning. Contacts to the sample holder are made in multiple mask steps with fine scale features created by deposition through a silicon membrane mask, fabricated in the Nanotools facility at McGill and with nanoscale features created by Focalized Ion Beam (FIB) at U. Sherbrooke.

Having developed the basic understanding of processes required to construct a planar molecular device on an insu-lator, we will continue to seek methods of templating mole-cular growth by tuning interactions, and to refine the fabri-cation of in situ metal electrodes. To create nanoscale gaps for a single molecule we will pursue methods of electromi-gration and characterize the resulting structures with high-resolution nc-AFM in order to integrate multi-scale metal electrodes with templating methods. Finally, manipulation of structures with the AFM tip will be explored as a method for fine-tuning self-assembled structures.

References

• “C60 on alkali halides: Epitaxy and morphology studied by noncontact AFM”, S.A. Burke, J.M. Mativetsky, S. Fostner and P. Grütter, Phys. Rev. B 76, 035419 (2007).

• “Templated growth of 3,4,9,10-perylenetetracarboxylic dianhydride molecules on a nanostructured insulator”, J.M. Mativetsky, S.A. Burke, S. Fostner and P. Grutter, Nanotechnology 18, 105303 (2007).

• “Nanoscale Pits as Templates for Building a Molecular Device”, J.M. Mativetsky, S.A. Burke, S. Fostner and P. Grutter, Small 3, 818 (2007).

• “Nucleation and Submonolayer Growth of C60 on KBr”, S.A. Burke, J.M. Mativetsky, R. Hoffmann and P. Grütter, Phys. Rev. Lett. 94, 096102 (2005).

The challenge of scale: in situ SEM image of sub-micron electrode structures with AFM cantilever, AFM of Ta wire, atomically defined molecular nanostructure with metal cluster contacts.

Constructing a single molecule device: Foundations and future


A recent breakthrough enabled us to show the first true demonstration that a single electron transistor (SET) can operate under normal electronic circuit conditions and even at temperatures exceeding 130oC. By combining a SET fabricated using RQMP major facility with a small nanostructure island, it is possible to produce a non-volatile memory device with an access time as fast as the random access memory that we find in today’s computers.

Researchers: Dominique Drouin and Jacques BeauvaisStudents: Christian Dubuc, Parekh Rutu, Jean-François Morissette, Pierre Markey and Arnaud BeaumontContact: Dominique Drouin; [email protected]; www.crn2.ca

Over the last 2 years, we have developed a radically new approach for the fabrication of single electron transistors. This approach has significantly altered the performance of the electronic devices, making it possible to observe for the first time nano-scale effects well above the tempera-ture required for common applications, such as integrated circuits for next generation computers and telecommunica-tion networks. In addition, our approach was intentionally constrained to techniques which can be integrated into the semiconductor industry manufacturing chain. The objective of this research project is to develop prototypes for very high speed non-volatile memory devices, which could com-pletely alter the architecture of desktop computers. An ini-tial study of the operation of the single electron transistors (SETs) fabricated with our technique demonstrated their effective operation at temperatures exceeding 130oC. This is the first true demonstration that a SET can function under normal operating conditions typical of electronic consumer products, opening the door to a multitude of applications which have been proposed in the literature without, how-ever, the possibility of implementation before this techno-logical breakthrough.

A process design based on a nanowire structure was demons trated in the RQMP micro/nanofabrication facility at Université de Sherbrooke with the fabrication of metallic single-electron transistors. The method is capable of sub-

attofarad resolution resulting in transistors that exhibited Coulomb blockade up to approximately 430 K. The shape of the nanoscale island in our SET device and the thickness

of the dielectric layer are critical parameters. The optimiza-tion of the vertical dimension is achieved by a “damascene” approach known where a process of chemical mechanical polishing (CMP) makes it possible to reduce the thickness of the device tunnel junctions to a few nanometers. The result is a robust and repeatable process which enabled us to fabricate SETs operating at very high temperatures. An analysis showed that these devices have sufficient opera-tional margin to sustain process fluctuations and still oper-ate within the temperature limits of conventional silicon field effect transistors. This could enable the fabrication of hybrid circuits using both MOSFET and SET device technology on the same substrate and the development of new memory technology that combines the high speed of random access memory and the enormous storage capacity of hard discs.

References


• “A nanodamascene process for advanced single-electron transistor fabrication”, C. Dubuc, J. Beauvais and D. Drouin, IEEE Transactions on Nanotechnology 7, 68 (2008).

IDS-VDS curve of prototype as a function of temperature. The temperatures are 296 K ( ), 336 K ( ) and 433 K ( ). All the data are for a grounded back-gate ex-cept the open circles ( ) where VGS is 0.3 V at 433 K turning the SET in ON mode.

Schematic illustration of the single electron transistor fabricated by the nano-damascene process.

Non-volatile memory based on single electron trap

54 | RQMP | PRojects | MagnetisM in MateRials and systeMs

The aim of this research is to search and study materials that possess a giant magnetocaloric effect at reasonable temperatures and modest magnetic field changes to be used in magnetic refrigeration. The principal advantage of magnetic refrigeration over conventional gas-liquid refrigeration is the absence of environmentally hazardous gas emissions. In our endeavors we have studies several materials with different structural types to gain an insight into how and why certain structural types and compositions can provide the best candidates for use in magnetic refrigeration. In parallel with the experimental studies we have carried out density functional theory calculations to understand the electronic band structure and magnetic ground states in an effort to improve the material properties via changes in composition or structure.

Magnetocaloric materials: Theory and experiment

Researchers: Zaven Altounian, Dominic H. Ryan and Xu Bo LiuCollaborators: J. M. Cadogan (U. Manitoba); M. Yue (Beijing University of Technology) Student: H.B. WangContact: Zaven Altounian; [email protected]; www.physics.mcgill.ca/~zaven/

Magnetic refrigeration, based on the magnetocaloric effect (MCE), has received increased attention as an alternative to the well-established compression–evaporation cycle for room-temperature applications. In the magnetic refrigera-tion cycle, randomly oriented magnetic moments are aligned by a magnetic field, resulting in heating of the material. On removing the field, the magnetic moments randomize, which leads to cooling of the material below ambient tempera-ture. Magnetic refrigeration is an environmentally friendly and does not use ozone depleting chemicals, hazardous chemicals or greenhouse gases. Another advantage in using magnetocaloric materials is the ~60% efficiency com-pared to 40% in the best gas-compression refrigerators. This higher energy efficiency will also result in a reduced CO2 release. The magnetocaloric effect has a peak near the magnetic transition temperature, Tc. Its value can be increased subs tantially if there is a 1st order structural tran-sition that occurs at the same time as the magnetic transi-tion. Our continuing studies include four distinct classes of material types. Here we present a brief summary of our progress in each case.

Rare-earth based materials, R5T4, where R = rare-earth and T = Si, Ge, or R5(Si,Ge,Sn)4. In order to explore new 5:4 magnetocaloric materials we studied the Gd5SixSn4-x

system using the low temperature synchrotron diffraction, magnetic measurements and 119Sn Moessbauer spectrosco-py. It is found that Gd5Sn4 shows a typical temperature and field induced magnetostructural transition at Tc. Similarly, a magnetostructural transition is also observed in Nd5SixGe4-x using the magnetic measurements and neutron diffraction. As a comparison, the non-magnetic system La5SixGe4-x was also studied.

Fe-based materials, the magnetocaloric compound La(Fe,Co,Si,Al)13 with a cubic NaZn13-type structure was found to be easily prepared using a melt-spun/annealing process route [1]. The temperature dependent 57Fe Moessbauer spectroscopy and magnetic measurements show that the replacement of Fe by Co and/or Si will increase TC and drive the magnetic transition at TC from a first order to a second order in La(Fe1-xCox)13-ySiy [1]. The

doping of a small amount of carbon in La(Fe0.88Al0.12)13 changes its magnetic state from antiferromagnetic to fer-romagnetic and show a large MCE. With further increasing C content, the magnetic transition is changed from a first order to a second order. It should be noted that the isother-mal magnetic entropy change of LaFe13-base compounds will decrease as the order of magnetic transition changes from a first order to a second order.

Mn-based materials: MnFe(P,As,Si,Ge) and Mn5(Si,Ge)3. Mn5Ge3 shows a second order magnetic transition and large MCE near TC = 298 K. The replacement of Ge by Si will decrease TC and MCE in Mn5(SixGe1-x)3 alloys [2]. Our recent calculations indicate that the exchange coupling parameters change substantially in MnFe(P,As,Si,Ge) with a hexagonal Fe2P-typed structure. The pair exchange parameters of Mn-Mn are also three times that of Fe-Fe. The magnetic state of Fe is metastable, which is responsible for the field induced first order magnetic transition near TC.

Laves compounds RCo2 shows large MCE and first order magnetic transition near TC for R = Dy, Ho and Er. By partial replacement of Er by Gd or by partial replacement of Co by Fe, the TC of ErCo2 increases from 33 K to 400 K and the MCE decreases with the addition of Gd and Fe [3]. Our first-principles calculations shows that the order of magnetic transition depends on whether a metastable low spin state of Co exists in RCo2-base compounds [3].

References

[1] “The order of magnetic phase transition in La(Fe1-xCox)11.4Si1.6 compounds”, X.B. Liu and Z. Altounian, J. Magn. Magn. Mater. 270, 305 (2004); “Structure and magnetic transition of LaFe13-xSix compounds”, X.B. Liu, Z. Altounian and D.H. Ryan, J. Phys: Condens. Matter. 15, 7385 (2003); “The structure and large magnetocaloric effect in rapidly quenched LaFe11.4Si1.6 compound”, X.B. Liu, Z. Altounian and G.H. Tu, J. Phys: Condens. Matter. 16, 8043 (2004).

[2] “Co magnetism and the order of the magnetic transition in Er1-xGdxCo2 Laves phases”, X.B. Liu, and Z. Altounian, J. Appl. Phys. 99, 08Q101 (2006).

[3] “Magnetocaloric effect in (Er1-xGdx)Co2 pseudobinary compounds”, X.B. Liu and Z. Altounian, J. Magn. Magn. Mater. 292, 83 (2005); “Magnetic states and magnetic transitions in RCo2 Laves phases”, X.B. Liu and Z. Altounian, J. Phys: Condens. Matter. 18, 5503 (2006).


The control of electromagnetic phenomena in materials is fundamental for a large number of technologies. The design of metamaterials based on the inclusion of metallic nanostructures, with a specific geometry, into a dielectric matrix, permits a degree of control of the electromagnetic properties. The use of nanostructured ferromagnetic materials offers novel possibilities for engineering the properties of these artificial materials at microwave frequencies.

Researchers: David Ménard and Arthur Yelon Collaborator: C. Caloz (Electrical Engineering, Polytechnique)Students: Fanny Béron, Louis-Philippe Carignan, Vincent Boucher, Christian Lacroix and Gabriel MonetteContact: David Ménard; [email protected]

The goal of this research project is to fabricate ferromag-netic nanowire arrays, to understand their electromagnetic properties and to develop novel microwave devices based on this understanding. Electromagnetic phenomena in mat-ter depend upon the characteristic impedance and disper-sion relation of the medium, which depend upon the mag-netic and dielectric properties of the material. The use of metallic and ferromagnetic elements in a dielectric matrix is the starting point of our approach to adjusting the imped-ance and the dispersion of the material.

Nanowire networks (diameter: 20-170 nm, length: several microns, density: near 109 nanowires/cm2) are obtained by electrodeposition of ferromagnetic metals into nanoporous alumina membranes. We prepare high permeability CoFeB alloys and magnetoresistive multilayers (alternation of mag-netic (Ni, Co or CoFeB) and non-magnetic (Cu) thin discs).

Ferromagnetic materials possess a rich spectrum of mag-netic excitations (magnons) tunable at microwave frequen-cies using an external applied magnetic field. This enables us to modify the magnetic permeability. The magnetore-sistive and magnetoinductive responses of the magnetic nanowires, combined with plasmonic resonances of the metallic structures, are used to control the electrical permit-tivity (magnetodielectric response) of the medium.

The intrinsic dispersion relations of the material will be modi-fied, with the goal of producing composite right/left-handed (CRLH) transmission lines. The CRLH concept, based on the

clever design of capacitors and inductances in a microwave planar circuit, offers many possibilities for engineering dis-persion relations at microwave frequencies (see Caloz and Itoh, Metamaterials for high-frequency electronics, Special issue Blue-Sky Electronic Technologies and their Implica-tions for the Future, Proc. IEEE 93, 1744 (2005)).

The use of ferromagnetic metallic inclusions, appropriately structured and organised in a dielectric matrix, should lead to the development of a new generation of magnetic meta-materials for high frequency devices.

References

• “First-order reversal curves diagrams of ferromagnetic soft nanowire arrays”, F. Béron, L. Clime, M. Ciureanu, D. Ménard, R.W. Cochrane and A. Yelon, IEEE Trans. Magn. 42, 3060 (2006).

• “Magnetic anisotropy in arrays of Ni, CoFeB and Ni/Cu nanowires”, L.-P. Carignan, C. Lacroix, A. Ouimet, M. Ciureanu, A. Yelon and D. Ménard, J. Appl. Phys. 102, 023905 (2007).

• “Electromagnetic properties of ferromagnetic nanowire arrays”, V. Boucher and D. Ménard, J. Appl. Phys. 103, 07E720 (2008).

Top view of a nanoporous alumina membrane

Side view of a nanowire array after dissolution of the alumina matrix

CRLH structure over a multilayer nanowire network used as a substrate

Ferromagnetic nanowire arrays for high frequency devices

56 | RQMP | PRojects | QuantuM PRoPeRties oF MateRials

This research project is on the study of the electronic properties of graphene, a single layer of graphite. We search for electron or skyrmion crystallization in graphene in the presence of a strong quantizing magnetic field. We expect such crystals to possess a pseudospin texture and one or more Goldstone modes in addition to the phonon mode. Some of these modes should be detectable in microwave absorption experiments.

Electron and skyrmion crystals in graphene

Researcher: René CôtéCollaborators: H.A. Fertig (U. Indiana); A.H. MacDonald (U. Texas) Students: J.F. Jobidon, J. Lambert, M.-A. Lemonde, W. Luo and D. Veilleux Contact: René Côté; [email protected]; www.physique.usherbrooke.ca/~rcote

Graphene is a single sheet of carbon atoms that can be extracted from graphite by micromechanical cleavage. The-oretical and experimental studies of this two-dimensional system have shown that its properties are very different from those of a conventional two-dimensional electron gas (2DEG) formed in semiconductor heterostructures. Gra-phene is a semimetal in which the carriers are described by the relativistic Dirac equation. They have a linear dispersion relation and a zero rest mass. In addition to their electronic spin, the carriers also have a pseudospin index which is related to the fact that graphene has a honeycomb lattice structure that can be described as a triangular lattice with a basis of two atoms.

Because the kinetic and potential energies both scale iden-tically with the density of carriers, a crystal of electrons is not expected to occur in graphene. In the presence of a transverse magnetic field, however, such crystallization is possible. In this project, we study the formation of crystal-line structures of electrons in single layer and bilayer gra-phene. Following previous work by Zhang and Joglekar (C.-H. Zhang and Yogesh N. Joglekar, cond-mat/0703026), we show that electron crystal states are indeed the ground state of the two-dimensional electron gas for some val-ues of its density if the pseudospin vectors are collectively aligned in some arbitrary direction so as to form a pseu-dospin magnet.

When the first Landau level is filled, however, each elec-tron added to the system generates a topological excita-tion known as “skyrmion”. This charged excitation has a vortex-like pseudospin texture. A finite density of skyrmions is expected to condense into a Skyrme crystal at very low temperature. We expect to show that skyrmion crystals are lower in energy than other crystalline states around integer filling. Since electrons must be described by a pseudospin in graphene, we also expect these skyrmion crystals to have collective motions involving position as well as pseu-dospin oscillations. Because of the particular symmetries of the peudospin texture in a Skyrme crystal, we anticipate also one or more Goldstone modes in addition to the usu-al phonon mode. We study how these modes modify the transport properties of the 2DEG in graphene and how they can be detected experimentally using microwave absorp-tion techniques.

This work is being done in collaboration with undergradu-ate and graduate students in my group and in collaboration with Prof. H.A. Fertig at Indiana University and Prof. A.H. MacDonald and his group at Texas University at Austin.

Computer time for this work is provided by the Réseau qué-bécois de calcul haute performance (RQCHP).

References

• “Collective modes of CP(3) skyrmion crystals in quantum Hall ferromagnets”, R. Côté, D.B. Boisvert, J. Bourassa, M. Boissonneault and H.A. Fertig, Phys. Rev. B 76, 125320 (2007).

• “Pseudospin vortex-antivortex with interwoven spin textures in double-layer quantum Hall systems”, J. Bourassa, B. Roostaei, R. Côté, H.A. Fertig and K. Mullen, Phys. Rev. B 74, 195320 (2006).

Figure 1. Electronic density in a crystal of electrons in graphene in a magnetic field. The arrows indicate the orientation of the pseudospins.


Quantum information processing is a new field of research that promises exponentially more powerful computers than those offered by current technology. To realize tasks that are impossible for their classical counterparts, quantum computers will harness effects (superposition of states, entanglement and interference) that are fundamentally quantum mechanical. The realization of such a quantum information processor is however an extremely difficult task. Electrical circuits based on superconducting materials are promising candidates for the realization of a quantum computer. These circuits also open new possibilities for the fundamental study of quantum mechanics and, in particular, for quantum optics.

Researcher: Alexandre BlaisCollaborators: R.J. Schoelkopf and S.M. Girvin (Yale); A. Wallraff (ETH Zurich)Students: Maxime Boissonneault, Jérome Bourassa and Kevin LalumièreContact: Alexandre Blais; [email protected]; www.physique.usherbrooke.ca/blais

Superconducting qubits are microfabricated nano-circuits based on Josephson junctions. Depending on the topology of the circuit into which the junctions are embedded and on the ratio of the Josephson to charging energies in these circuits, one can realize various types of superconducting qubits. These qubits encode quantum information in differ-ent degrees of freedom of the circuit: charge, flux or phase. To behave quantum mechanically, these circuits must be extremely well decoupled from any external sources of noise. Moreover, they must be strongly coupled to external gates to allow for fast control and read-out. Fulfilling these two contradictory requirements simultaneously is the main challenge in designing and operating solid-state qubits.

With colleagues from Yale University, we have developed a new proposal for a Josephson junction based quantum computer. The architecture, shown in Figure 1, consists of a superconducting charge qubit capacitively coupled to the center electrode of a high quality superconducting trans-mission line resonator. An attractive feature of this system is that the coherent resonator-qubit coupling can exceed the rate of photon decay out of the resonator and the qubit’s dephasing and relaxation rates.

In the high quality limit, the resonator acts as a simple har-monic oscillator and the system can be mapped to a two level system (the qubit) strongly coupled to a harmonic oscil-lator. This is the situation traditionally studied in quantum optics and, in particular, in cavity quantum electrodynamics (cavity QED) where a single atom strongly couples to the vacuum field of an optical or microwave cavity. This system can be described by the Jaynes-Cummings model of quan-tum optics and leads to very rich physics in the presence of noise and external perturbations. Using this mapping,

this architecture is therefore an on-chip realization of cavity QED, something that is now called circuit QED. This opens new possibilities both for the study of quantum optics in solid state systems and for quantum information process-ing with superconducting electrical circuits.

Circuit QED is theoretically studied in the group of Alexandre Blais at the Université de Sherbrooke. This is done in very close collaboration with experimental groups at Yale University and ETH Zurich. Circuit QED as been used to demonstrate the first observation of vacuum Rabi splitting at the level of a single photon and single (artificial) atom in a solid-state device, the longest relaxation time in a superconducting circuit (~7 ms) and the coherent entangle-ment of a pair of superconducting qubits. It was also used to measure non-destructively single microwave photons and for the first controlled generation and observation of Berry’s phase in a superconducting system.

References

• “Quantum information processing with circuit quantum electrodynamics”, A. Blais, J.M. Gambetta, A. Wallraff, D.I. Schuster, S.M. Girvin, M.H. Devoret and R.J. Schoelkopf, Phys. Rev. A 75, 032329 (2007).

• “Resolving photon number states in a superconducting circuit”, D.I. Schuster, A.A. Houck, J.A. Schreier, A. Wallraff, J.M. Gambetta, A. Blais, L. Frunzio, B. Johnson, M.H. Devoret, S.M. Girvin and R.J. Schoelkopf, Nature 445, 515 (2007).

• “Coupling superconducting qubits via a cavity bus”, J. Majer, J.M. Chow, J.M. Gambetta, J. Koch, B.R. Johnson, J.A. Schreier, L. Frunzio, D.I. Schuster, A.A. Houck, A. Wallraff, A. Blais, M.H. Devoret, S.M. Girvin and R.J. Schoelkopf, Nature 449, 443 (2007).

Figure 1. Circuit QED: a charge qubit capacitively coupled to a transmission line resonator

Figure 2. Theoretical and experimental results for the non-destructive measure-ment of single microwave photons.

Quantum optics and quantum information processing with superconducting circuits


Quantum electromechanical systems consist of a quantum mesoscopic conductor (e.g. a single electron transistor or quantum point contact) which is coupled to a micron to nanometre scale mechanical resonator (i.e. a doubly clamped beam). We have developed theoretical approaches to describe the quantum dissipative physics of these systems, and have applied these to understand recent experiments in the field.

Researcher: Aashish ClerkCollaborators: K.C. Schwab (U. Cornell) Students: D. Wahyu-Utami and S.B. BennettContact: Aashish Clerk; [email protected]; www.physics.mcgill.ca/~clerk/

One typically thinks of a quantum electromechanical sys-tem as an excellent position detector, as in these systems changes in the position of the resonator lead to a measur-able change in current through the conductor. However, a corresponding part of the physics is that the dynamics of electrons (or Cooper-pairs or quasiparticles) in the conduc-tor will affect the dissipative physics of the oscillator. This “back-action” effect can be particularly subtle, as the con-ductor is typically far from a thermal equilibrium state, and typically does not have Gaussian noise properties. As such, the conductor acts as a very novel kind of quantum dissi-pative system. We have been interested in trying to under-stand theoretically the consequence of such effects.

Recent work from our group has predicted some unusual effects that can occur in these systems. For example, we predicted that in a system comprising of a superconducting single-electron transistor coupled to a double-clamped beam, the noise of tunneling, out-of-equilibrium Cooper pairs can be used to cool the resonator to near its ground state. This “back-action” cooling effect was recently seen in experiment. We have also predicted a related laser-like instability in this system, which has an interesting con-nection to the physics of a single-atom laser.

Our current work focuses on understanding the conditional dynamics in these systems, as well as understanding how systems incorporating a qubit could be used to probe true quantum effects in the resonator.

Schematic of a superconducting single-electron transistor coupled to a nanome-chanical resonator (i.e. a beam).

References

• “Laser-like instabilities in Quantum Nano-Electromechanical Systems”, S.D. Bennett and A.A. Clerk, Phys. Rev. B 74, 201301 (2007).

• “Using a qubit to measure photon number statistics of a driven, thermal oscillator”, A.A. Clerk and D. Wahyu Utami, Phys. Rev. A 75, 042302 (2007).

• “Cooling a nanomechanical resonator with quantum back-action”, A. Naik, O. Buu, M.D. LaHaye, A.D. Armour, A.A. Clerk, M.P. Blencowe and K.C. Schwab, Nature (London) 443, 193 (2006).

Effective temperature of tunnelling Cooper-pairs as a function of control voltages on a superconducting single-electron transistor.

Theory of quantum electromechanical systems


Resistively detected nuclear magnetic resonance (RDNMR) studies were performed on GaAs/AlGaAs two dimensional electron systems in the quantum Hall regime. At higher Landau levels, application of an RF field at the nuclear resonance frequency coincides with a measured minimum in the magnetoresistance, as predicted by the hyperfine interaction picture. Near n =1 however, an anomalous “dispersive” line shape is usually reported. We find that the anomalous line shape is not universal but instead depends in an interrelated way on a number of parameters. We further find evidence that the minima and maxima of the dispersive shape possibly originate from two distinct mechanisms.

Researcher: Guillaume GervaisCollaborators: H.L. Stormer (Alcatel-Lucent Technologies and U. Columbia, USA); L.N. Pfeiffer and K. West (Alcatel-Lucent Technologies, USA)Student: Cory DeanContact: Guillaume Gervais; [email protected]; www.physics.mcgill.ca/~hedbergj/labpage/home.htm

Resistively detected nuclear magnetic resonance (RDNMR) has emerged as a powerful tool for studying the integer and fractional quantum Hall states in 2D electronic systems. However, while RDNMR offers the potential to gain new insight into a wide range of interesting many body elec-tron physics, features in the measured signal remain unex-plained. In the RDNMR technique, RF radiation is applied to the sample at the nuclear resonant frequency, causing a de-struction of the nuclear polarization. Since the nuclear spins couple to the electrons (via the hyperfine interaction), varia-tions in the nuclear polarization are detected in the electron transport (resistance). This coupling between the nuclear and electron spins therefore gives a direct probe of the elec-tronic spin states, and further allows us to perform NMR with

far greater sensitivity than possible with conventional NMR techniques. However, while the simple hyperfine interaction picture predicts a minima only response in the measured resistance, in the vicinity of the n =1 quantum hall state an anomalous “dispersive’’ line shape is observed, where the usual resistance minimum is followed by a secondary resis-tance maximum at slightly higher RF frequency. A careful study of the RDNMR signal in the vicinity of n =1 showed

that the anomalous line shape is not universal, but instead depends in an inter-related way on a number of para meters including filling factor, electronic temperature, and even the parameters of the applied RF field (Figure 1). We also found that applying a strong DC current bias causes a complete inversion of the signal (Figure 2), similar to a temperature

correlated inversion reported elsewhere. The position of the inverted signal observed here however does not coincide with the initial minimum, but is instead down-shifted. This shift in the resonance position, together with the evolution from a minimum only, to dispersive, to a maximum only, sug gests the inversion is not a simple temperature correla-ted flip, but instead results from a more complex process. This result further suggests that the minima and maxima signals possibly originate from two distinct mechanisms. This research has been supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the Alfred P. Sloan Foundation, and the RQMP.

Figure 1. Variation of RDNMR line shape with (a) filling factor, (b) sample tempera-ture, and (c) applied RF power

References

• “Resistively Detected NMR in Quantum Hall States: Investigation of the anomalous line shape near n = 1”, C.R. Dean, B.A. Piot, L.N. Pfeiffer, K.W. West and G. Gervais, Physica E 40, 990 (2008).

• “Evidence for Skyrmion Crystallization from NMR Relaxation Experiments”, G. Gervais, H.L. Stormer, D.C. Tsui et al., Phys. Rev. Lett. 94, 196803 (2005).

Figure 2. Evolution (inversion) of the RDNMR line shape with applied DC current bias

Resistively detected NMR in quantum hall states


We present an investigation into the manipulation of nuclear spins near the n =1 quantum Hall state of GaAs/AlGaAs using optical pumping methods. For this, we have built a custom-designed polarization controller which allows for arbitrary polarizations of near-infrared laser light to be transmitted through fiber optics onto the sample. Using resistive readout, it is demonstrated that different polarizations of light induces specific changes in the transport properties in the first Landau level of the GaAs/AlGaAs quantum well.

Researcher: Guillaume GervaisCollaborators: M.P. Lilly and J.L. Reno (Center for Integrated Nanotechnologies (CINT), USA)Student: Jonathan M. BusetContact: Guillaume Gervais; [email protected]; www.physics.mcgill.ca/~hedbergj/labpage/home.htm

Recent advances in the growth and micro-fabrication of semiconducting materials have shown high promises in de-vices operating by virtue of the properties of the electronic spin, rather than its charge as in conventional electronics. This push toward ‘spintronic’ type devices is motivated by the greater degree-of-freedom provided by spins, and also their higher level of isolation from the environment which makes their quantum-mechanical states less prone to de-coherence. The nuclear spins of GaAs offer even greater isolation from the environment, and show great potential as quantum information carriers if it is possible to effectively initialize, control, and readout their quantum-mechanical states. The multiple quantum coherence of the GaAs nu-clear spins has recently been detected locally by resistive methods, and the rather long coherence times in the milli-second range certainly makes them appealing for the imple-mentation of quantum algorithms. The preliminary results of our investigation demonstrate that different polarizations of light induce specific changes in the transport properties in the first Landau level of the GaAs/AlGaAs quantum well.

The method that we are using to try and interact with the GaAs nuclear spins is via the optical Overhauser effect where light in the near-infrared spectrum (l = 800 nm) with a well-defined circular polarization is used to create a large, out-of-equilibrium nuclear spin polarization. Since the effec-tive coupling of the Overhauser effect is optimal for light with circular polarization, and minimal for linear polarization, controlling the polarization of the light in situ offers a simple way to manipulate the polarization of a small ensemble of nuclear spins.

In order to efficiently pump the GaAs nuclear spins opti-cally at low laser power circularly polarized light in the near-infrared spectrum is required. This is normally difficult to achieve with optical fibers due to varying birefringence. In order to overcome this limitation, a polarization controller was built that can transmit any polarization of light onto the sample by simply rotating a series of l/4 and l/2 wave-plates. A schematic diagram of the polarization controller is shown in Figure 1.

The preliminary results of our investigation are shown in Fig-ure 2. The map on the left is output polarization as a function of waveplate angles (a and b), where maxima correspond to

circularly polarized light (s) and minima correspond to out-put of linear polarized light (||). The map on the right shows changes in the resistance Rxx. A clear correlation is shown where the regions of right hand circularly polarized light (s+) correspond to the local maximas of Rxx and the regions of left hand circularly polarized light (s-) correspond to the local resistance minimas. This research is done in collaboration with Sandia National Laboratories and has been supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), FQRNT, the Alfred P. Sloan Founda-tion, and the RQMP.

Figure 1. Schematic diagram of the custom polarization controller using a novel back-reflection measurement technique. (Mack, 2007)

Figure 2. Two maps showing the relationship between polarization of light and the quantum Hall transport resistance Rxx.

References

• “Towards optical manipulation and resistive readout of the GaAs nuclear spins”, J.M. Buset, A.H. Mack, D. Laroche, C.R. Dean, M.P. Lilly, J.L. Reno and G. Gervais, Physica E: Low-dimensional Systems and Nanostructures 40, 1252 (2008).

• “Local control of light polarization with low-temperature fiber optics”, A.H. Mack, J. Riordon, C.R. Dean, R. Talbot, G. Gervais, Optics Lett. 32, 1378 (2007).

Investigation into the optical manipulation and resistive readout of the GaAs nuclear spins


We use an ultrasonic velocity and attenuation technique to characterize the pressure-temperature phase diagram of organic conductors. Elastic waves couple easily with charge and spin degrees of freedom in these materials. In quasi-2D k-(BEDT-TTF)2Cu[N(CN)2]Br, we have identified a phase separation between magnetism and superconductivity at low temperatures that could explain why there is still controversy about the symmetry of the superconducting order parameter in these systems. In 1D (TMTSF)2(ClO4)(1-x)(ReO4)x we are interested in measuring the ultrasonic attenuation in order to identify the symmetry of the order parameter.

Researchers: Mario Poirier, Kim Doan Truong and Claude BourbonnaisCollaborators: K. Bechgaard (Denmark); P. Auban-Senzier and D. Jérome (Orsay )Students: Alexandre Langlois and Maxime DionContact: Mario Poirier; [email protected]

Ultrasonic attenuation is a very powerful tool to probe the symmetry of the order parameter because of its angular sensitivity. In organic conductors, controversy is still running about this symmetry since experimental results are contra-dictory. The ultrasonic technique was never used before in organics because the samples are too small and brittle. A few years ago we succeeded in adapting the pulse echo technique to these materials and we could map the phase diagram of the 2D k-(ET2)X compounds with the ultrasonic velocity (Figure 1). At ambient pressure, the compound with X = Cu[N(CN)2]Br is metal located in the right portion of the diagram. It was thus believed that it was the ideal system to study the superconducting order parameter.

Recently, we could finally measure the attenuation in the superconducting state (12 K) as a function of frequency. We discovered that a phase separation occurs in this compound contrary to the general belief. We could identify through dif-ferent thermal cycles and through magnetic field studies that an antiferromagnetic phase at 15 K competes with su-perconductivity at 12 K. Hysteresis was also observed and interaction between the two phases at the domains walls impedes any clear determination of symmetry of the order parameter. However, anomalies on the velocity for differ-ent polarizations of the ultrasounds suggest that it could be a mixture of s- and d-wave. We are now studying the compound with x = Cu(SCN)2 located deeper in the metallic phase and for which no phase separation is expected.

In the 1D organic conductors (TMTSF)2ClO4, superconduc-tivity is induced below 1.2 K if the crystal is cooled very slowly. In this system, p-wave superconductivity has been suggested but experiments are more controversial. The identification of the order parameter is thus important and we will use the ultrasonic attenuation to try obtain the sym-metry. Experiments are on going. Microwave conductivity is also programmed in a dilution refrigerator to obtain the tem-perature dependence of the magnetic penetration length.

To perform these experiments we are equipped with a 18 Tesla magnet, a VTI for experiments between 2 and 300 K, a dilution refrigerator for T as low as 20 mK. The organic are also highly compressible, so we have high pressure cells (clamped and gas) with 12 Kbar maximum pressure.

Figure 1. Pressure-Temperature phase diagram of k-(ET2)Cu[N(CN)2Cl from ultra-sonic velocity anomalies.

References

• “Competition between magnetism and superconductivity in the organic metal k-(BEDT-TTF)2Cu[N(CN)2]Br”, D. Fournier, M. Poirier and K.D. Truong, Phys. Rev. 76, 054509 (2007).

• “Magnetoelastic coupling in hexagonal multiferroic YMnO3 using ultrasound measurements”, M. Poirier, F. Laliberté, L. Pinsard-Gaudart and A. Revcolevschi, Phys. Rev. B 76, 174426 (2007).

Elastic properties of quasi-1D and -2D organic superconductors


Ytterbium ions infrared and visible cooperative luminescences, resulting from YAG laser and selective site excitations, in Yb doped Y2SiO5 single crystal (5%) and thin film (6%) are studied. Magnetically coupled Yb-Yb ion pairs seem to play a major role in energy transfer and cooperative emission confirming prevalence of superexchange mechanisms in such system.

Researcher: Serge JandlCollaborators: Ph. Goldner, O. Guillot-Noël and B. Viana (École Nationale Supérieure de Paris)Students: A. Denoyer and Y. LévesqueContact: Serge Jandl; [email protected]

Yb3+-based laser materials present many advantages resulting from a simple electronic structure, with two mani-fold levels 2F7/2 ground-state and 2F5/2 excited state, which prevents cross-relaxation quenching and up-conversion effects. Yb-doped Y2SiO5 (Yb:YSO) thin films and single crystals have been recently studied by Raman spectros-copy and infrared transmission. In particular, the crystal-field (CF) levels of the two Yb3+ ions occupied sites in Y2SiO5 have been detected with their vibronic side bands, and Yb3+-Yb3+ magnetically coupled pairs have been ob-served. Cooperative luminescence, originating from yt-terbium ions, corresponds to a process in which two Yb3+ excited ions make downward transitions emitting one pho-ton with the sum of the two transitions energies. Besides YbPO4, other ytterbium activated hosts emit cooperative luminescence, centered around 500 nm, under infrared excitation. A general theory based on electric multipole-multipole interactions between optically active 4f elec-trons in lanthanide systems was developed. It was recently applied in ytterbium doped CsCdBr3 by comparing the experimental and theoretical cooperative luminescence rates resulting from dipole-quadrupole and forced dipole-dipole interactions. A different theoretical approach to cooperative luminescence, based on a generalization of the superexchange mechanism between dimers of lanthanide ions bridged by ligands, has been proposed. Y2SiO5 crys-tallizes in the C2/c monoclinic space group and Yb3+ ions enter the two non-equivalent and equally populated YI and YII sites of C1 symmetry. According to preliminary infrared absorption studies of Yb:YSO, (see figure) in addition to YbI and YbII isolated ions absorption bands around 10189 and 10215 cm-1 respectively, presence of interacting Yb3+-Yb3+ pairs is manifest in satellite absorption bands (e.g. 10206 and 10220 cm-1) located at D + J/2 and D - 3J/2, where D corresponds to the Yb3+ isolated ion CF transition and J to the pair exchange coupling constant.

In this project we focus on the observed cooperative lumi-nescence of Yb 6%:YSO thin film and Yb 5%:YSO single crystal. By comparing emissions and transmissions in the infrared and visible ranges following Tm3+ impurity assisted absorption and sites selective excitations; role and contri-bution of isolated ions and magnetically coupled pair ions are analyzed.

Infrared transmission spectra of Yb 5% :YSO single crystal (a) and Yb 6%: YSO thin film (b) at T = 13 K. Absorption bands of Yb3+Isolated ions in sites I and II are indicated.

Reference

• “Annealing optical effects on Yb-doped Y2SiO5 thin films”, A. Denoyer, S. Jandl, F. Thibault and D. Pelenc, J. Phys: Condens. Matter 19, 156222 (2007).

Cooperative emission study in ytterbium doped Y2SiO5


Compounds containing metallic oxides can exhibit spectacular properties, such as superconductivity above liquid nitrogen temperature. Already the most powerful magnets on earth are made of superconductors, as are the most sensitive magnetic field detectors. Metal oxides can also exhibit spectacular magnetic properties. But to realize the full potential of these promising materials it is necessary to develop new theoretical methods, namely computer simulations and mathematical understanding of the quantum mechanical laws that lead to these properties. This research program applies and develops new theoretical tools to understand and predict properties of this class of compounds that challenges traditional views.

Researchers: André-Marie Tremblay and David Sénéchal Collaborators: Gabi Kotliar (Rutgers); Anne-Marie Daré, Gilbert Albinet, Laurent Raymond (Marseille) Students: Louis-François Arsenault, Dominic Bergeron and Dominique ChasséPostdocs: Bumsoo Kyung and Syed HassanContact: André-Marie Tremblay; [email protected]; www.physique.usherbrooke.ca/tremblay

A major focus of our research is high-temperature super-conductors. One of the reasons is that they can be mod-eled by the paradigm for correlated electrons on a crystal-line lattice, namely the one-band Hubbard model. Solving this problem for cuprates opens the way to the solution of much more complicated cases that include longer-range interactions or more bands, such as the cobaltates, vanadates and colossal magnetoresistance materials. High-temperature superconductors are a spectacular example, but by no means a unique example, of correlated materi-als whose understanding requires new approaches, beyond textbook Solid State Physics. Heavy fermions, colossal magnetoresistance materials and organic superconductors are among the list. Using new simulation methods, we have already obtained generic phase diagrams for the cuprates and for layered organic materials that include competition with antiferromagnetism and spin liquids and are in remark-able agreement with experiment. The figure illustrates other types of results.

Phase diagramsWe are presently working on the generalized phase diagram of high-temperature supercon-ductors, in other words the full dependence on doping, interaction strength and frustra-tion in order to gain insight into the mechanism for d-wave superconductivity. We are also working on determining the properties of the pseudogap phase at high temperature.

TransportTo make connection with experiment, much work remains to be done to develop methods appropriate to understand transport. This is being done for electron-doped systems using the Two-Particle Self-Consistent Approach that we have developed. We are planning studies based on so called “Quantum Cluster Approaches”.

New directionsCold atoms in optical lattices offer the possibility to control the microscopic Hamiltonian and hence to act as models of condensed matter systems, allowing close comparison between theory and experiment. We have recently predic-ted the appearance of new supersolid phases on the two-dimensional triangular lattice.

We are starting a program of study of interfaces of correla-ted materials. These are important for device applications and also for fundamental studies of new interface-states of matter. New RQMP collaborators will join this project: Claude Bourbonnais, René Côté and Alexandre Blais.

InfrastructureFor numerical calculations we use local Beowulf clusters in addition to RQCHP supercomputers.

References

• “Interaction-Induced Adiabatic Cooling for Antiferromag-netism in Optical Lattices”, A.-M. Daré, L. Raymond, G. Albinet and A.-M.S. Tremblay, Phys. Rev. B 76, 064402 (2007).

• “Mott Transition, Antiferromagnetism, and d-wave Super-conductivity in Two-Dimensional Organic Conductors”, B. Kyung and A.-M.S. Tremblay, Phys. Rev. Lett. 97, 046402 (2006).

• “Pseudogap and high-temperature superconductivity from weak to strong coupling. Toward quantitative theory.”, A.-M.S. Tremblay, B. Kyung and D. Sénéchal, Low Temperature Physics 32, 561 (2006).

Calculated wave-vector dependent pho-toemission cross-section (left) compared with experiment (right) on high Tc compound.

Superconductivity, antiferromagnetism and new phases of matter in correlated materials


Vortices are fascinating entities which interact with each other and form a variety of different phases, such as an Abrikosov lattice, Bragg glass, disordered phase, as well as smectic and liquid-like phases depending on the magnetic field and the driving force. In this project we concentrate on superconducting glasses, who constitute a unique opportunity to study vortex motion because of the very low depinning threshold. We also develop novel processing methods for superconductors such as MgB2 with a high potential for technological applications.

Researchers: Michael Hilke, Zaven Altounian and Dominic RyanCollaborator: M. Pekquleryuz (Metals/Materials Engineering, U. McGill)Students: Josianne Lefebvre and Ying Ling YinContact: Michael Hilke; [email protected]; www.physics.mcgill.ca/~hilke

Four years ago we obtained the experimental phase dia-gram of moving vortices, which was featured on the cover page of Phys. Rev. Lett. We used a very clean (low pinning) superconductor, which incidentally has a highly disordered atomic structure. Indeed, the very pure NiZr2 based super-conducting glass has a very weak pinning strength because of the absence of order on a length scale of a single vor-tex (about 30 nm at high magnetic fields). More recently we mapped out the transverse motion of vortices in similar sys-tems [1] (Figure 1).

Quite strikingly, we observed huge features of transverse motion associated with the transition to the highly mobile smectic-like depinned phase. These results unravel many questions on the nature of these different phases, in the regime of high driving forces and high density of vortices.

Some of the other results, include, mapping out the entire phase diagram of vortex dynamics in an extremely low pin-ning superconducting glass and the discovery of an orien-tational transition in the vortex dynamics just before the peak effect.

We are also interested in novel superconductors, such as magnesium diboride, where thin films were successfully fabricated using the RQMP sputtering facility at McGill as shown in Figure 2.

In addition to thin films of magnesium diboride we also developed superconducting coatings, which can be used to coat almost any type of material and enhance them with superconducting properties. Using thermoplastic polymer based on ethylcellulose we were able to obtain a supercon-ducting coating with a high critical temperature, reaching the value of the bulk crystal of 39 K. This opens up interest-ing new technological applications, which rely on dissipa-tion less transport.

Figure 2. Magnesium diboride thin film fabricated by sputtering and subsequent annealing. The superconducting transition temperature is shown for different an-nealing temperatures as well as the current-voltage characteristics for different magnetic fields.

Reference

[1] “Transverse vortex dynamics in superconductors”, J. Lefebvre, M. Hilke, R. Gagnon and Z. Altounian, Phys. Rev. B 74, 174509 (2006).

Figure 1. The curves represent the phase diagram obtained from the longitudinal resistance of the vortex motion in a NiZr based superconductor. The color map as a function of B and I represents the value of the Hall resistance.

Vortex dynamics and novel superconductors


Strongly correlated electron systems such as high critical temperature superconductors, present complex phase diagrams with many phases either coexisting or competing. These result in many phenomena appearing at the atomic scale, also having consequences on the macroscopic scale. In order to better understand these phenomena, we need a real space, local probe that works down to the atomic scale. Such a probe is scanning tunneling microscopy and spectroscopy. We use this technique in order to explore these complicated materials in order to elucidate their microscopic theory.

Researchers: Christian Lupien and Patrick FournierCollaborators: A. Damascelli (U. British-Columbia); H. Takagi (U. Tokyo)Students: Behnaz Behmand, Jean-Charles Forgues and Jonathan VermetteContact: Christian Lupien; [email protected]; www.physique.usherbrooke.ca/lupien

Strongly correlated electron systems is a general name for materials with strong interactions between the electrons which leads to many interesting behaviors. An example is the high critical temperature (high-Tc) superconduc-tors. They have a very complex phase diagram showing the presence of various types of order and which, after 20 years, still cannot be explained fully. A complete theory of these materials would help to control their characteristics which would help their usage but it could also lead to room temperature superconductivity which would have numer-ous and important application in sectors like electricity transport and medical diagnostic (cheaper magnetic reso-nance imaging scanners).

The difficulty in understanding these materials comes from their complex phase diagrams which show the presence of various orders that compete or coexist. Some of these phases, like the pseudogap, have not been properly identi-fied yet. Because of the strong correlations and the various phenomena present in these systems, they can show important structures at the atomic scale. These produce effect in the bulk, but in order to better identify and under-stand them, a more direct microscopic view of these fea-tures is important.

We use a scanning tunneling microscope, an instrument that has atomic resolution and can therefore measure nano-scale structures at the surface of samples. A powerful varia-tion of that technique is to obtain spectroscopic information (conductance curve) at every point in space of topograph (map of the atomic structure) in order to have real space local spectroscopic information. The conductance, for sim-

ple models, can be related the local density of states which is calculable theoretically.

Recent measurements on some members of the high-Tc superconductors have shown interesting features such as checkerboard charge density order and glassy variation of the electronic density. Further experiment on various other members of this class of materials and under different conditions are needed to properly identify and understand these results.

Topographic map showing the atoms on the surface of NaCCOC a high-Tc material. The inset is a zoom showing the absence of a single atom.

Conductance map (left) and its Fourier transform (right) showing a checkerboard electron organization over the same area as the topographic map.

References

• “An intrinsic bond-centered electronic glass with unidirectional domains in underdoped cuprates”, Y. Kohsaka, C. Taylor et al., Science 315, 1380 (2007).

• “A “checkerboard” electronic crystal state in lightly hole-doped Ca2-xNaxCuO2Cl2”, T. Hanaguri, C. Lupien, Y. Kohsaka, D.-H. Lee et al., Nature 430, 1001 (2004).

Phase diagram for the hole doped high-Tc materials with various phases such as superconductivity (dSC), antiferromagnetism (AFM) and pseudogap (PG).

Nanoscale electronic structure of strongly correlated electron systems


Understanding the role of disorder in two-dimensional electron systems is crucial, since it affects most physical properties. Disorder can take on many forms, such as impurities, crystal defects, or intrinsic material properties. In this project we investigate the role of different types of disorder in a variety of systems, including semiconductor based heterostructures and monolayers of graphene.

Researchers: Michael Hilke, François Schiettekatte and Thomas SzkopekCollaborators: E. Diez and J.M. Cerver (Salamanca, Spain); D. Shahar (Weizmann Inst., Israel); A.Y. Cho (Bell labs); J.C. Flores (Arica, Chile) Students: S. Avesque, M. Wu and V. YuContact: Michael Hilke; [email protected]; www.physics.mcgill.ca/~hilke

This work is done in collaboration with many research-ers from all over the world, including Chile, Israel, US and Europe. This is necessary because of the complexity and diversity of systems and kinds of disorder present in mate-rials. For instance, in the illustration below, different scat-tering mechanism are shown, which are relevant in very clean GaAs/AlGaAs heterostructures. These devices are very important for applications in high frequency electron-ics because of their very high mobilities. One of the stud-ies we undertook, was the characterization of implanted defects in these structures in order to better understand the role of defects in the physics of strongly correlated sys-tems, like fractional quantum Hall states [1].

In the opposite limit of short range disorder, as present in many alloys, materials such as InGaAs/InAlAs based ones show interesting quantum phase transitions in the quantum Hall regime [2]. The theoretical concepts describing differ-ent kinds of disorder can often be expressed in terms of a disorder correlation length. The knowledge of this length scale has important implications on basic properties such as, for instance, the density of states [3].

Another interesting recently discovered material, the gra-phene monolayer, promises great potential for technologi-cal applications, because of their intrinsic high mobility. In order to better understand these new materials we devel-oped new experimental and modeling tools in order to shine

light on the role of disorder in these systems. In Figure 2, we show an example of graphene flakes and of how these systems can be modeled.

An important tool in this work was the use of the RQMP ion implantation system at UdeM, this system alloyed for the controlled implantation of different types of ions in the semiconducting heterostructures.

Figure 2. Top: Example of graphene flakes (a & b): optical image, (c) SEM image, (d) AFM image. Bottom: illustrates the basics for modelling graphene transport.

References

[1] “Correlations vs impurities: or how to go from fractions to integers in the quantum Hall effect”, S. Avesque, M. Hilke, F. Schiettekatte, M. Chicoine, L.N. Pfeiffer and K.W. West, Proceedings, Nanoelectronics 06, Lancaster (2006).

[2] “Density of states of disordered systems with a finite correlation length”, J.C. Flores and M. Hilke, Phys. Rev. B 73, 125115 (2006).

[3] “Two-dimensional electron gas in InGaAs/InAlAs quantum wells”, E. Diez, Y.P. Chen, S. Avesque, M. Hilke, E. Peled, D. Shahar, J.M. Cerver, D.L. Sivco and A.Y. Cho, Appl. Phys. Lett. 88, 052107 (2006).

Figure 1. Illustration of the different scattering mechanisms in GaAs based het-erostructures.

Disorder in two-dimensional electron systems


The recent observation of quantum oscillations in YBa2Cu3O6.5, a material of the high-Tc cuprate superconductors family, by Prof. Louis Taillefer (N. Doiron-Leyraud et al., Nature 447 p. 565 (2007), has partly lifted the veil on the 20 year old mystery of high-Tc superconductivity. These quantum oscillations, and transport properties in high magnetic fields more generally, are direct probes of the fundamental electronic properties of those remarkable materials, and are a powerful way to reveal their secrets.

Researcher: Louis TailleferCollaborators: D.A. Bonn, Ruixing Liang, W.N. Hardy (ICRA, UBC); Cyril Proust (LNCMP, France); Luìs Balicas (NHMFL, USA)Postdoctoral fellows: Nicolas Doiron-Leyraud and Ramzy DaouStudents: Jean Baptiste Bonnemaison, Francis Laliberté, Olivier Cyr-Choinière and David Le BoeufContact: Louis Taillefer; [email protected]; www.physique.usherbrooke.ca/taillefer/

Superconducting materials can show a quantum phenom-enon at the macroscopic scale: the pairing of charge carri-ers, carrying the current coherently, without any resistance. While conventional superconductors show this fascinating property at temperatures (below the critical temperature, Tc) close to the absolute zero, high-Tc cuprate superconduc-tors can show this quantum strangeness up to tempera-tures close to half room temperature (150 K). This factor two separating the critical temperature and room temperature has been the object of great hope. Indeed, if we could over-come this factor two, superconductivity could arise in our daily lives. This would have major consequences in energy transport and storage, and on different aspects of our tech-nology that we are not even able to imagine now. The con-sequences would be of the same scope of those caused by silicon based semiconducting materials. The research we are involved in today hence consists mainly of discover-ing the underlying mechanism of superconductivity, and to control it in order to tune the Tc up to room temperature.

The whole family of cuprate materials has a common fea-ture which is the copper-oxygen plane. The carrier concen-tration in those planes can be tuned by chemically doping the system. Our work is mainly carried out on YBa2Cu3Oy crystals, provided by a CIFAR collaboration with crys-tal growing experts at the University of British Columbia. Figure (a) shows the phase diagram of YBa2Cu3Oy. Super-

conductivity appears between an insulating state (at low doping) and a metallic state (at high doping). One of the fundamental questions raised by this diagram is wether the superconducting ground state is an insulator or a metal. The answer of this crucial question will come from the observation of quantum oscillations (illustrated in the figure on the left) [1]. Those oscillations are observed under extreme magnetic fields, of the order of 106 times the Earth’s magnetic field. Such fields are provided by the French national high magnetic field facility (LNCMP, Toulouse), and the experiment was performed there in collaboration with Cyril Proust. These oscillations are a direct probe of the Fermi surafce, an elegant theoretical concept that distin-guishes between occupied and unoccupied states of charge carriers in a virtual space. The observation of the Fermi sur-face via quantum oscillations is unambiguous evidence for the metallic nature of high-Tc superconductors. Neverthe-less, the observed Fermi surface (Figure (b) on the right) is significantly different from the one observed at higher dop-ings via a spectroscopic probe (Figure (c) on the right). The recent study of Hall effect [2], another high field transport property, in collaboration with Cyril Proust (LNCMP) and Luìs Balicas of the national high magnetic field laboratory in the USA (NHMFL), has brought a tremendous understanding of this topological difference in the Fermi surface. It appears now to be clear that a phase transition must occur at some point of the phase diagram to link the two observed Fermi surfaces. The understanding of the origin of this phase tran-sition, and the connection with superconductivity itself is very promising and might eventually reveal the very inner nature of high-Tc superconductors.

References

[1] “Quantum oscillations and the Fermi surface in an underdoped high-Tc superconductor”, N. Doiron-Leyraud, C. Proust, D. LeBoeuf, J. Levallois, J.B. Bonnemaison, D.A. Bonn, R. Liang, W.N. Hardy and L. Taillefer, Nature 447, 565 (2007).

[2] “Electron pockets in the Fermi surface of a hole-doped high-Tc superconductors”, D. LeBoeuf, N. Doiron-Leyraud, J. Levallois, R. Daou, J.B. Bonnemaison, N.E. Hussey, L. Balicas, B.J. Ramshaw, R. Liang, D.A. Bonn, W.N. Hardy, S. Adachi, Cyril Proust and L. Taillefer, Nature 450, 533 (2007).

YBa2Cu3Oy properties: Left : illustration of quantum oscillations. Right : (a) phase diagram, (b) and (c) : Fermi surfaces at two dinstinct dopings.

Exploration of the Fermi surface in high-Tc cuprate superconductors


Currently available viral diagnostics methods are relatively slow, expensive and restricted to a single viral pathogen or family. Ideally, it would be useful to identify rapidly and simultaneously a broad spectrum of viruses. This research aims at developing a quantum semiconductor-based biosensor for the rapid detection and typing of human viral pathogens. One axis of the research concerns so-called epitaxial quantum dot biosensor (eQD), while the second axis is defined by a monolithically integrated quantum well surface plasmon resonance (QW-SPR) biosensor.

Researcher: Jan J. DubowskiCollaborators: Eric Frost, Emanuel Escher and Sophie Michaud (Faculty of Medicine, U. Sherbrooke); Nelson Rowell and Zbig Wasilewski (IMS-NRC Canada); Farid Bensebaa (ICPET-NRC Canada) Students: Alex Voznyy, Ximing Ding, Khalid Moumanis, Greg Marshall and Dominic LepageContact: Jan J. Dubowski; [email protected]; www.gel.usherbrooke.ca/crn2/pages_personnel/dubowski/accueil_en.htm

To overcome some of the key technological problems and limitations related to the application of colloidal QDs for biodetection, we have proposed a device based on an array of epitaxial QDs (eQD) that has been grown directly on semiconductor substrate by thin film deposition technology. The idea of an eQD biosensor is summarized in Figure 1. A wafer with eQD’s emitting at a specific wavelength is functionalized with biotinylated antibodies of different ana-lytes, or DNA-based bait molecules. Upon excitation, each eQD, which typically is 20 - 40 nm in diameter at its base, will emit photoluminescence (PL) radiation in a rapidly expanding cone. This radiation is expected to be modified in the presence of nano-objects, such as trapped viruses immobilized above.

We have carried out extensive research aimed at bio- functionalization of the surface of GaAs — the material of choice for capping InAs eQD’s. The goal is to provide con-ditions suitable for direct trapping of different viral patho-gens on the GaAs surface. We have studied passivation of (001) GaAs with various thiols and we determined condi-tions for the deposition of biotin and successful immobiliza-tion of avidin. Our ab-initio calculations of thiol-GaAs inter-actions have indicated that the thiol-GaAs binding energy exceeds 44 kcal, which supports our observations con-cerning the stability of various biomolecules immobilized on

thiolated surfaces of GaAs. The important conclusion of this part of the research was that the strong binding energy of

thiol-GaAs, places this material system at par with a well known thiol-Au system, and validates the potential of GaAs as an attractive material for binding different bio-moieties. Another approach for biosensing investigated in our group is based on the surface plasmon resonance (SPR) effect. We have invented a new quantum semiconductor micro-structure that allows a significant increase in the propaga-tion length of SPs propagating above semiconductor sur-face. The core of the invention is a dielectric adaptive layer of SiO2 that separates the Au grating from the semicon-ductor (GaAs) substrate comprising a quantum well (QW) buried below the surface. The proposed solution offers the possibility of constructing a monolithically integrated SPR biosensing device. Such a device, while offering sensitiv-ity comparable to that of the best conventional (prism-based) SPR analyzers, will be highly compact, accurate and reliable due to the elimination of external sources of the SPR excitation.

The optical methods of interrogating both eQD and QW-SPR biosensor surface as well as the compact biosen-sor microstructure have the potential to offer a rapid and easily accessible, e.g., at the point-of-care, detection of multipathogens in parallel.

Fabrication and testing of the investigated biosensors have been carried out in the RQMP supported laboratories. Com-puter time for modeling the GaAs-thiol interface has been provided by the Réseau québécois de calcul de haute per-formance (RQCHP).

References

• “Surface plasmon assisted photoluminescence in GaAs–AlGaAs quantum well microstructures”, D. Lepage and J.J. Dubowski, Appl. Phys. Lett. 91, 163106 (2007).

• “Structure, bonding nature and binding energy of alkanethiolate on As-rich GaAs (001) surface: a density functional theory study”, O. Voznyy and J.J. Dubowski, J. Phys. Chem. B 110, 23619 (2006).

• “Immobilization of avidin on (001) GaAs”, X. Ding, Kh. Moumanis, J.J. Dubowski, E. Frost and E. Escher, Appl. Phys. A 83, 357 (2006).

Figure 1. A schematic architecture of the eQD biosensor. Detection of the eQD photoluminescence is used to monitor the surface state of the biosensor.

Quantum semiconductor biosensor


High-temperature superconductors belong to a family of materials whose properties change from insulator to superconductor as a function of “dopant” (such as oxygen) concentration. The nature of the phase that appears near the insulating phase when superconductivity is destroyed by a magnetic field is one of the mysteries that may hold the key to understanding the whole phase diagram. We are studying the possibility of structural rearrangement (stripes) using advanced density-functional theory approaches as well as the possibility of short-range antiferromagnetic order to explain recent experimental data.

Researchers: Michel Côté, André-Marie Tremblay and David SénéchalStudents: Simon Pesant and Louis-François ArsenaultContact: Michel Côté; [email protected]; www.phys.umontreal.ca/~michel_cote

Material known as high-temperature superconduc-tors (high-Tc) have been discovered over 20 years ago. Despite much progress, we do not yet have a complete theory that could explain their unusual behavior. Such understanding would help to guide our search for novel superconductors, bringing us closer to the goal of finding a high-Tc material that could operate at room temperature.

A recent important discovery made by RQMP re-searchers might help shine some light on this prob-lem. They observed quantum oscillations under in-tense magnetic fields in un-derdoped high-temperature superconductors YBa2Cu3Oy. This proves the existence of a Fermi surface in under-doped systems near the insulating phase, a subject that had been much debated before. Further transport experiments have proven that even in hole-doped compounds, an electron-like Fermi surface can appear. This is a very counter-intuitive behavior that requires a new look at this problem. A pos-sible explanation would be that the electrons of this system reorganize themselves in superstructures known as “stripes”. Such structures (reconstructed Fermi surfaces) are often observed in other compounds. However, in YBa2Cu3Oy, spectroscopic probes do not show their presence, even though simple phenomenological models suggest that they could explain the quantum oscillation experiments.

The groups of Michel Côté from the Université de Montréal, André-Marie Tremblay and David Sénéchal from the Université de Sherbrooke have joined their efforts to try to resolve this mystery. Their approach is based on a combined model Hamiltonians and first principle calcula-tions approaches. First, density-functional theory (DFT) calculations are used in order to compute the electronic properties of the doped YBCO solid. This system is par-ticularly challenging for standard approaches in DFT since correlations among the conducting electrons are difficult to take into consideration. More advanced techniques like the LDA+U that borrow method from model Hamiltonians will be investigated in order to see if “striped” configurations could be stable in this material for a range of dopings. In parallel, phe-nomenological studies will be performed to

try to understand under what conditions short-range order could allow quantum oscillations to be observed without full Fermi surface reconstruction [1].

InfrastructureFor the intensive numerical calculations, the project uses the supercomputers of the RQCHP as well as a Beowulf clusters at the Université de Sherbrooke.

Reference

[1] “Pseudogap and Spin Fluctuations in the Normal State of Electron-Doped Cuprates”, B. Kyung, V. Hankevych, A.-M. Daré et A.-M.S. Tremblay, Phys. Rev. Lett. 93, 147004 (2004).

Electronic charge density of a copper-oxide plane in YBa2Cu3Oy computed using density-functional theory.

Role of Fermi surface reconstruction in high-temperature superconductors


Semiconductor quantum dots find applications in optoelectronic devices such as lasers and infrared detectors and constitute promising candidates as effective qbits, the basic elements of quantum computers. This project seeks to elucidate the physical processes that control the escape of the carriers localized in quantum dots at temperatures close to 300 K.

Researchers: Patrick Desjardins, Richard Leonelli , Remo Masut and Carlos SilvaCollaborator: Sylvain Raymond (NSERC) Students: Guillaume Gélinas and Benoit GosselinContact: Richard Leonelli; [email protected]; www.mapageweb.umontreal.ca/leonelli/

Quantum dots are artificial assemblies of atoms of nano-metric size that confine the electronic wave function in all three dimensions of space. Because of their discrete den-sity of states, quantum dots find applications as efficient optoelectronic devices such as lasers and infrared detec-tors. They are also considered as very promising candidates as “qbits”, the building blocks of quantum computers.

Notwithstanding the field of application, the understanding of the physical processes that control carrier capture and thermal escape is crucial for the development of efficient devices at room temperature. These processes remain a subject of debate: do the e-h pairs — or “excitons” — cap-tured in a quantum dots escape as a pair or as indepen-dent carriers? Why is the emission intensity much smaller at 300 K than at 5 K?

Our project seeks to answer these questions through an original study of a generic system: InAs/InP quantum dots. These dots have the shape of a thin, truncated pyramid. Their emission is multimodal, as up to eight families of quan-tum dots, that arise by 1-monolayer variations of the thick-ness of the pyramids, can be observed on the same sample [1]. As each family is characterized by a specific activation energy, carrier transfer occurs between the families as the

temperature is increased. This is exemplified on Figure 1, where the intensity of the two higher energy peaks continu-ously decreases with temperature while that of the lower energy ones initially increases before decreasing when T reaches 200 K.

This complex behavior will be analyzed through a model based on the principle of detailed balance, as schematized on Figure 2. However, this model requires to accurately determine the capture and radiative rates as well as the exciton confinement energies.

We will grow carefully designed samples with non-radiative centers intentionally introduced in the InAs wetting layer or the InP barrier. The samples will be characterized with temperature- and intensity-dependant photoluminescence spectra, time-resolved photolumines-cence spectra, and photoluminescence excitation spectra.

Figure 1. PL spectra of InAs/InP QDs as a function of temperature from 5 K (top) to 295 K (bottom). The emission from the wetting layer and from three QD families that differ by in thickness by an integer number of monolayers can be distinguished.

Figure 2. Schematic representation of the coupled transfer rate equation model used to extract quantitative information from the experimental data.

Reference

[1] “Optical emission from InAs/InP self-assembled quantum dots: evidence for As/P intermixing”, A. Lanacer, N. Shtinkov, P. Desjardins, R.A. Masut and R. Leonelli, Semicond. Sci. Technol. 22, 1282 (2007).

Exciton thermal escape in self-assembled quantum dots


Electrostatic force microscopy (EFM) is a powerful tool to investigate the electrical properties of nanometer-scale electronic devices. We apply the EFM for investigating the electronic structure of a single quantum dot (QD). We successfully observed the single-electron charging in epitaxially grown self-assembled InAs quantum dots by the force measurement. More elaborate experiments will reveal the internal energy level structure of such a single QD. The technique is also applied to investigate the spatial and temporal charge fluctuations in nanometer-scale electronic devices.

Researchers: Peter Grütter, Yoichi Miyahara and Ashish ClerkCollaborators: Andy Sachrajda, Sergei Studenikin and Philip Poole (IMS-NRC)Student: Lynda CockinsContact: Peter Grütter; [email protected]; www.physics.mcgill.ca/~peter

Quantum dots (QDs) are often referred to as ‘artificial atoms’ as they exhibit the discrete energy levels in their electronic structure as atoms do due to their small size. It is important to understand how the structure of QDs such as shape and size is related to their electronic structure as the variation of the energy levels is technically relevant in such applications as semiconductor lasers and quantum cellular automata. We are working towards determining the energy levels in single QDs by measuring electrostatic force from the elec-tric charge in QDs by a cryogenic atomic force microscope (AFM) which is sensitive to the weak electrostatic force by a single electron charge.

Our AFM oscillates a cantilever with a sharp metallic tip at distances on the order of nanometers above the sample. We monitor the shift in resonance frequency of the cantilever, which is caused by the change in the tip-sample interaction force. In particular, the electrostatic force is dominant under the application of the tip-sample bias voltage. By scanning the tip over the sample, one can build a spatial map of the electrostatic force on the sample with nanometer resolution, or the tip can be held in one place to gain information on one location.

By positioning the tip over a InAs QD (Figure 1) and sweep-ing the bias voltage, discrete shifts in the cantilever fre-quency occur which indicate sudden changes in the force. These changes are the result of a single electron entering (or leaving) the QD. The simul-taneously measured damping of the cantilever shows peaks at the same voltages where

the electrons entered the QD (Figure 2). This means that a part of the energy in the oscillating cantilever is transfered to the charge in the QD.

Theoretical predictions by Prof. A. Clerk show that the damping data as a function of temperature will yield the internal energy levels of a QD. Experiments under the mag-netic field should also enable to yield the same information. Our cryogenic AFM equipped with a 8T superconducting magnet is capable of both experiments. In this way, we can systematically investigate a number of QDs with different size and shape.

This technique allows us to measure the spatial and tem-poral fluctuation of the electrostatic field and is applied to study such fluctuations in nanometer-scale electronics devices, which is also of great technological relevance.

Figure 1. AFM image of InAs QD.

Figure 2. Frequency shift (red) and damping (green) vs. bias voltage measured on InAs QD.

References

• “High-aspect ratio metal-tips attached to atomic force microscopy cantilevers with controlled angle, length and radius for electrostatic force microscopy”, L. Cockins, Y. Miyahara, R. Stomp and P. Grutter, Rev. Sci. Instrum. 78, 113706 (2007).

• “Detection of single electron charging in an individual InAs quantum dot by noncontact atomic force microscopy”, R. Stomp, Y. Miyahara, S. Schaer, Q. Sun, H. Guo, P. Grutter, S. Studenikin, P. Poole and A. Sachrajda, Phys. Rev. Lett. 94, 056802 (2005).

• “Determination of Tc, Vortex Creation and Vortex Imaging of a Superconducting Nb Film using Low Temperature Magnetic Force Microscopy”, M. Roseman and P. Grutter, J. Appl. Phys. 91, 8840 (2002).

Electronic structure of single quantum dots investigated by electrostatic force microscopy at 4.5 K


We are constructing a scanning probe microscope that is capable of operating at dilution refrigerator temperatures of 50 mK and magnetic fields of 16 T. The microscope is based on a tuning fork sensor. Slip-stick motors in conjunction with capacitive sensors allow coarse positioning of the sample and the scanning unit. This instrument holds promise to investigate various exotic quantum states accessible at these conditions.

Ultra low temperature scanning probe microscope

Researchers: Peter Grütter, Guillaume Gervais, Michael Hilke, Roland Bennewitz and Aashish ClerkStudents: James Hedberg and Dr. Vera SazonovaContact: Peter Grütter; [email protected]; www.physics.mcgill.ca/spm

Scanning probe microscopy is a widely used and power-ful technique capable of not only studying surfaces at the atomic level, but also of probing the spatial structure of vari-ous phenomena. Depending on the type of probe installed, it can be sensitive to different types of interactions: from atomic, to electrostatic, to magnetic forces. Alternatively, the operation can be turned around, and the probe can be used to influence the sample locally. Combining this tech-nique with ultra low temperatures and high magnetic fields opens doors to probing and manipulating various exotic quantum states that form at these extreme conditions.

Our microscope is based on a quartz tuning fork with a sharp Si cantilever attached to one of the prongs. As the tip is rastered over the surface it is subjected to the forces from the sample. Their spatial gradients act as an additional spring to the tuning fork, changing its frequency. By track-ing the resonance frequency (or amplitude) of the tuning fork as a function of tip position, we can build a spatial map of sample-tip interactions.

The microscope is mounted on a dilution refrigerator with a base temperature of 50 mK in the bore of a 16 T magnet. Much care was taken insure vibration isolation from the outside. The probe is mounted on top of the scanning pi-ezo tube; the sample is mounted upside down above it (see Figure 1). The coarse positioning systems implemented by slip-stick motors and capacitive position sensors will allow us to do coarse sample positioning and coarse approach to the sample at the base temperature. The microscope’s operation is controlled by room temperature electronics.

As a first step we demonstrated the functionality of the microscope at ambient conditions and at liquid nitrogen temperature. The standardized spacing, size and depth of the DVD pits (shown on Figure 2) allowed us to calibrate the piezoelectric constants at different temperatures. The sta-bility of the microscope is demonstrated by imaging atomic steps on KBr at 4 K and a field of 15 T — the highest mag-netic field AFM image ever! This image did not measurably move as the field was ramped from 0-15 T. We are now processing to perform measurements at 50 mK.

Figure 1. A photograph and a schematic of the microscope

Figure 2. An image of DVD pits taken at 77 K

Figure 3. KBr at 4 K and 15 T. Atomic steps are clearly visible.


adVanced chaRateRiZation and FaBRication oF noVel MateRials

We are studying the interfacial interactions of metal nanoparticles with carbon nanotubes. For applications such as fuel cells, where the catalytic reaction providing the electrical current occurs at the nanoparticle surface, strong interfacial adhesion prevents the nanoparticles from diffusing across the CNT surface, and coalescing. Because CNTs are non-reactive, the covalent bonds giving strong adhesion cannot take place without the introduction of chemical groups to which the nanoparticles can bond. We are studying the introduction of such groups by several means, and their effect on adhesion. The overall aims of our study are to control the surface density and size of the deposited nanoparticles.

Controlling metal nanoparticle dispersion on carbon nanotubes through understanding their interfacial interactions

Researchers: Edward Sacher and Alain RochefortCollaborators: J.-P. Dodelet (INRS-ÉMT); M. José-Yacamán (U. Texas at Austin) Students: M.-A. Bostetter, B. Hennequin, S.-H. Sun, D.-Q. Yang and G.-X. ZhangContact: Edward Sacher; [email protected]; www.polymtl.ca/recherche/rc/professeurs/details.php?noprof=147

The fused ring system of the carbon atoms making up the graphene structure of carbon nanotubes (CNTs) is called an alternant hydrocarbon. Except at the CNT edges, each carbon atom is bonded to three others, with its remain-ing bonding electron forming a delocalized orbital system. Such a delocalized system is chemically unreactive, so that any metal nanoparticle (NP) deposited onto it can only bond weakly to it, through orbital overlap [D.-Q. Yang et al., Appl. Surf. Sci., 165, 116 (2000)]. The stronger bonds necessary for good adhesion must be formed through the introduction of chemical groups into the graphene structure. This is done through mild, controlled, repeatable, thoroughly character-ized reactions. Such reactions must do minimal damage to the CNTs while introducing evenly distributed groups with a large surface density.

The control of such reactions, taking place on the nano-scale, depends on our ability to characterize what is hap-pening. Our group has spent the last eight years develop-ing the techniques and the understanding that makes such characterizations possible. Our arsenal includes instrumen-tation for studying both nanoscale chemistry and morphol-ogy. The combination of these two methods provides not only a view of the NP resting on the surface but, as well, its interfacial chemical make-up.

Among the functionalization techniques we have explored, using these methods, are ion bombardment, reactive plasma etching, aqueous sonication, mixed sulfuric/nitric acid oxidation and p-p interaction. The latter technique is particularly advantageous in that it forms no bonds to the CNT and, thus, does no damage. In addition, when the p-p functionality is reacted with metal nanoparticles, virtually the entire surface of the CNT is covered.

An example of p-p functionalization: a CNT totally covered with < 2 nm Pt nanoparticles after functionalization with benzyl mercaptan.

References

• “X-ray photoelectron spectroscopic analysis of Pt nanoparticles on highly oriented pyrolytic graphite, using symmetric component line shapes”, G.-X. Zhang, D.-Q. Yang and E. Sacher, J. Phys. Chem. C 111, 565 (2007).

• “XPS demonstration of p-p interaction between benzyl mercaptan and multiwalled carbon nanotubes and their use in the adhesion of Pt nanoparticles”, D.-Q. Yang, B. Hennequin and E. Sacher, Chem. Mater. 18, 5033 (2006).

74 | RQMP | PRojects | adVanced chaRateRiZation and FaBRication oF noVel MateRials

One of the great experimental challenges in physics and chemistry is to obtain a real-time view of chemical reactions and material phase transitions by resolving the atomic motions during the breaking and making of chemical bonds, or the changes in a material’s atomic configuration on the pathway between phases. Femtosecond electron diffraction is a new experimental technique that holds the promise of being able to resolve such motions, effectively producing a ‘molecular movie’ of these microscopic processes.

Femtosecond electron diffraction: Making atomic-level movies of molecules and materials

Researcher: Bradley J. Siwick Collaborators: Jom Luiten and Marnix van der Wiel (Eindhoven, The Netherlands)Students: Chris Godbout, Robert Chatelain, Vance Morrison and Thana GhunaimContact: Bradley J. Siwick; [email protected]; www.physics.mcgill.ca/~siwick/

Virtually all of Chemistry and much of Condensed Matter Physics, it has been famously said, can be understood in terms of the ‘jiggling and wiggling’ of atoms. To be able to directly observe these motions requires the ability to obtain atomic level structural information on the timescale of a single vibrational period (~10-13 s). Until recently, no experimental technique was able to simultaneously provide both the necessary spatial and temporal resolution to pro-duce atomic-level movies of microscopic processes.

Femtosecond electron diffraction, however, combines the tools and techniques of ultrafast laser spectroscopy with those of electron microscopy in a novel way to provide these details. First, an ultrashort laser pulse excites the sys-tem (molecule or material) into an excited/nonequilibrium state. Second, at a controllable delay after the excitation, an ultrashort electron pulse is scattered off the sample and an electron diffraction pattern is recorded. The electron diffrac-tion pattern contains a wealth of information on the ‘instan-taneous’ atomic configuration of the specimen, so if several diffraction patterns are collected at different times after exci-tation — in a stroboscopic manner — they can be sequenced together to produce a ‘movie’ of the atomic motions.

The first ‘proof of principle’ study performed with this ap-proach was the laser-induced melting of polycrystalline alu-minum. The results are shown in the figure below. We were able to determine from this work that the Al melted from the inside-out through a process called homogenous nucleation, unlike the surface nucleated melting that is more familiar. The material is also superheated to 1.5 times the normal melting temperature before the phase transition occurs. For the further development of this technique it is essen-tial to have improved electron sources. In collaboration with a group in Eindhoven, The Netherlands, we are currently investigating approaches used in the particle physics com-munity which promise a 3 - 4 orders of magnitude enhance-ment in performance. This will enable the investigation of much more complex systems.

An atomic-level view of melting (a) Diffraction patterns showing the progress of a laser-induced polycrystalline to liquid phasetransition in Al. The structural rearrangements take only 3.5 ps (1 ps = 10 -12 s) (b) The face centered cubic (FCC) structure of Al. Atoms have been colour-coded such that each colour represents a given distance from the central black atom. (c) The time-dependent spectrum of interatomic spacings, G(r,t), at different stages through the phase transition.

(a)

(c)

References

• “An Atomic-Level View of Melting Using Femtosecond Electron Diffraction”, B.J. Siwick, J.R. Dwyer, R.E. Jordan, R.J.D. Miller, Science 302, 1382 (2003).

• “A sub-100 fs electron source for single-shot ultrafast electron diffraction in the 100 keV range”, T. van Oudheusden et al., J. Appl. Phys. 102, 093501 (2007).

(b)


Disordered materials play an important role in the electronic industry. For example, amorphous silicon is used as a transistor in liquid crystal flat displays. This material is also considered as the simplest example of the large family of disordered covalent materials that include amorphous semiconducting alloys, vitreous silica, and chalcogenide glasses. We are interested here in understanding, through experimental and theoretical approaches, what it means for disordered materials to be of good quality. This question is highly non-trivial as it means defining what is a good and a bad disordered and understanding the nature and the role of defects in these noncrystalline systems.

Researchers: Laurent Lewis, Normand Mousseau, Sjoerd Roorda and François SchiettekattePostdoctoral fellow: Ali KerracheStudents: Houssem Kallel, Jean-François Joly, Gabriel Geadah-Antonius and Philippe St-JeanContact: Normand Mousseau; [email protected]; www.phys.umontreal.ca/~mousseau

Silicon is at heart of the electronic industry. More of the time, it is used in its crystalline state, where all the atoms are aligned perfectly, placed in rows that repeat them almost infinitely. From time to time, positional errors occur in this perfect world, introducing defects in the crystalline order. For example, it can happen that an atom is missing, leav-ing a hole in the crystal, called vacancy. It can also that an atom cannot find a place in the lattice and must site in a free space off the crystal’s regular lattice, forming an intersti-tial. We now have a very good general understanding of of these so-called self-defects in Silicon but also in the other crystalline materials. But how can we apply these concepts to disordered materials who do not have well-aligned at-oms and uniquely defined atomic positions. This is the case of amorphous Silicon, an other phase of Silicon used, for example, in flat liquid-crystal displays. Here, atoms are no longer aligned but are placed in a random manner, respect-ing a single rule: each Silicon atom must have 4 neighbours, just as in the crystal. Now, what is the meaning of an atom missing (vacancy) or one too many (interstitial)? At this point, nobody knows.

In addition to having a great technological importance, amor-phous Silicon is considered the model system for all cova-lent disordered materials, such as silica, polymers and chal-cogenide glasses, adding to its interest. While the question of defects in amorphous Silicon has been around for thirty years, it is still open and the team assembled here to study the question is uniquely qualified to provide the definitive answer. It includes four world specialists in the matter, two theoreticians — Laurent J. Lewis and Normand Mousseau — and two experimentalists — Sjoerd Roorda and François Schiettekatte, all members of RQMP. With access to the massively parallel supercomputers of the Réseau québécois de calcul de haute performance as well as to the particle accelerators of the Département de physique of Université de Montréal, the researchers are in an exceptional position to make significant progress on this question and, in particu-lar, to identify clearly the nature of defects that are observed indirectly in experimental relaxation experiments.

The importance of this research is both fundamental and applied. From the fundamental point of view, for example, it will be very interesting to finally understand what constitutes a defect in disordered materials, i.e., what is out of place In a system that is also out-of-order. From the applied side, a better understanding of the atomic structures responsible for specific unwanted electronic properties could allow the development of compensation mechanisms that could im-prove significantly the use of amorphous silicon and other disordered materials for the electronic and optical industry.

Model of amorphous silicon. Each atom is an environment similar to that of the crystal while the material is overall disordered.

References

• “Dependence of the structural relaxation of amorphous silicon on implantation temperature”, J.-F. Mercure, R. Karmouch, Y. Anahory, S. Roorda and F. Schiettekatte, Phys. Rev. B 71, 134205 (2005).

• “Energy landscape around a minimum in a-Si”, F. Valiquette and N. Mousseau, Phys. Rev. B 68, 125209 (2003).

• “Evolution of the potential-energy surface of amorphous silicon”, H. Kallel and N. Mousseau, in preparation.

Structure of amorphous silicon — defects, local order and relaxation


Using x-ray intensity fluctuation spectroscopy, we study the microscopic origins of viscoelasticity of rubber using an in-situ stress strain cell. By heterodyning we are able to separate the local flow from dissipation.

Researchers: Mark Sutton and Luc PichéCollaborators: F. Livet, F. Bley (I.N.P.G), F. Ehrburger-Dolle, E. Geissler and I. Morfin (U. Joseph Fourier) Contact: Mark Sutton, McGill; [email protected]; www.physics.mcgill.ca/~mark/

Rubber is capable of large reversible elastic extensions, a characteristic that originates in the network formed on mesoscopic length scales from the crosslinking of poly-mer chains and the use of filler particles. Certainly, the best known use of rubber is in the making of tires. We are using in-situ stress-strain measurements combined with x-ray intensity fluctuation spectroscopy (XIFS) to address the microscopic origins of these mechanical properties. Observations suggest that these properties of rubber result from the coupled effects of interpenetrating networks of cross-linked polymers and filimentary aggregates of filler particles. One point of view uses the idea of jamming, first developed for granular materials, with the arrest in dynam-ics due to crowding of neighboring particles [2].

Experiments are carried out at the IMMY/XOR-CAT (8-ID) beamline at APS (Argonne, IL, USA) [2]. Experiments use a new technique we have developed, x-ray intensity fluctua-tion spectroscopy using heterodyning [3].

Figure 1. Example fit. Black contour to simple correlation function. Red contour with applied corrections for finite regions of averaging.

References

[1] “Jamming is not cool anymore”, A.J. Liu and S.R. Nagel, Nature 396, 21 (1998).

[2] “Structure and dynamics of concentrated dispersions of polystyrene latex spheres in glycerol: Static and dynamic x-ray scattering”, D. Lumma, L.B. Lurio, M.A. Borthwick, P. Falus and S.G. Mochrie, Phys. Rev. E 62, 8258 (2000).

[3] “X-ray intensity fluctuation spectroscopy by heterodyne detection”, F. Livet, F. Bley, F. Ehrburger-Dolle, I. Morfin, E. Geissler and M. Sutton, J. Synch. Rad. 13, 453 (2006).

We are studying a suite of model rubber systems. The under-lying polymer is either ethylene-propylene-rubber (EPR) or a closely related system based on ethylene, propylene and a non-conjugated diene (EPDM). Samples of each are filled with either carbon black or silica particles. Each system can also be synthesized with varying amounts of cross-linking and with varying volume fractions of fillers. This allows us to systematically vary the important variables controlling the elastic properties of rubber.

The correlation function for a heterodyne experiment devel-ops oscillations under flow. The envelope (or damping) of these oscillations is a direct measure of dissipation. Thus, XIFS with heterodyning measures both advection and dis-sipation effects from the equation of motion. This is particu-larly powerful for the study of visco-elastic effects. Here we show preliminary results for aerosil particles in crosslinked EPDM. The correlation functions depend on wave-vector, and the direction f with respect to the local flow. Figure 1 shows such a correlation function with the intensity scale being the degree of correlation. The oscillations are easily seen and so is their dependence on f. Superimposed on the data are contours from fitting a simple damped exponential with a frequency that varies with f. These fits are quite rea-sonable and give good estimates of v and f0 the direction of the flow. (f0 = 291.7° and t = 88.03 at q = .008 Å-1). The ve-locity is v = 3.09 Å/s. Much work remains, but it is clear that unique information on the behaviour of visco-elastic effects in filled rubber systems is obtained with this technique.

Visco-elastic properties of rubber


Pulsed laser ablation in liquid (PLAL) and laser-induced fragmentation (LIF) has been introduced for the direct synthesis of nanomaterials in a various kind of environment. This technique allows the formation of metallic (Au, Ag, Ni, Fe, Co, etc.) and semiconducting (Si, Ge, etc.) nanoparticles with controllable size distribution by varying the laser parameters and the liquid environment. Being made in aqueous solution of biocompatible ligands, the nanoparticles show improved biocompatibility due to the restricted surface contamination usually encountered by traditional chemical reduction methods. LIF is also developed for the size control, alloying and the formation of complex nanostructures.

Researcher: Michel MeunierCollaborators: Andrei Kabashin (Polytechnique); Françoise Winnik (U. Montreal); Paras Prasad (SUNY, Buffalo, USA); Lothar Lilge (U. Toronto, Ontario)Research Associate: Teko Napporn; Post-doc: Marie LaferrièreStudents: Sébastien Besner, Paul Boyer, David Rioux and Étienne Boulais Contact: Michel Meunier; [email protected]; http://lpl.phys.polymtl.ca/

Due to their unique physical and chemical properties, inorganic nanomaterials are now being integrated in a wide range of biomedical applications, slowly replacing the tra-ditional organic bio-markers. However, biocompatibility issues greatly slow down their introduction in real in-vivo applications. Toxicity arises either from the intrinsic toxic compounds composing the nanomaterials (e.g. Se) or from toxics by-products contaminating the particles surface. To solve this toxicity problem, we have introduced the femto-second laser ablation and fragmentation in aqueous solu-tion of biocompatible protective agents for the synthesis of metallic and semiconducting nanomaterials (Figure 1).

This two steps technique allows us to finely control the size of the particles between 2 and 30 nm with size dispersion competing with the traditional chemical synthesis method which requires toxic reducing and capping agents. As shown in Figure 2, very low dispersed gold nanoparticles were achieved in pure water using this laser processing. Collaborative works with Dr. Prasad from the University of Buffalo demonstrated a significant improvement of the low concentration Surface Enhanced Raman Scattering (SERS) signal using those particles due to the unique cleanness of their surface.

References

• “Synthesis of colloidal nanoparticles during femtosecond laser ablation of gold in water”, A.V. Kabashin and M. Meunier”, J. Appl. Phys. 94, 7941 (2003).

• “Fragmentation of colloidal nanoparticles by femtosecond laser-induced supercontinuum generation”, S. Besner, A.V. Kabashin and M. Meunier, Appl. Phys. Lett. 89, 3 (2006).

• “Two-step femtosecond laser ablation-based method for the synthesis of stable and ultra-pure gold nanoparticles in water”, S. Besner, A.V. Kabashin and M. Meunier, Appl. Phys. A - Mater 88, 269 (2007).

We will pursue this unique synthesis method for the pro-duction of complex structures such as alloys and core-shell structures in water-based environments for biomedical applications such as singlet oxygen production in photo-dynamic therapy (Lothar Lilge), photothermal therapy and SERS bio-detection. Our Co and Ni nanoparticles are amor-phous and superparamagnetism is observed at sizes above the theoretical transition to ferromagnetism. The fact that our magnetic nanoparticles are amorphous opens up the possibility to control the strength of the exchange energy by annealing, modifying the surface contribution to the overall magnetization and making soft materials.

Figure 1. Femtosecond PLAL (left) and white-light supercontinuum LIF in water (right)

Figure 2. 20 nm gold nanoparticles produced in pure water by PLAL and LIF.

Laser based “green” synthesis of non-toxic nanoparticles for biomedical applications


For the past few years, a revolution has taken place in the III-V semiconductor industry. Fabrication of nitride-based blue and UV LED is a hot topic. These devices will be at the heart of solid state lighting solutions as well as medical and environmental applications for UV light sources. There is still a large amount of research to be carried out in order to improve the devices efficiencies and reduce their unit cost in order to allow their widespread development.

Researchers: Vincent Aimez, Richard Arès, Dominique Drouin, Richard LeonelliCollaborators: G. Huminic and H. Helava (The Fox Group Inc., Pointe Claire, Quebec) Students: Rym Feriel Leulmi and Colin-Nadeau BrosseauContact: Vincent Aimez; [email protected]; www.crn2.ca/pages_personnel/aimez/

In collaboration with The Group Fox, our work is aimed at the improvement of GaN LED microfabrication process that yields LEDs with better performance. Our approach is based on ICP etching and LED surface modification as ways to improve photon emission.

Presently, the biggest problem with blue LED’s efficiency comes from GaN’s large refractive index which prevents most of the generated photons to escape from the device thus limiting its efficiency. It has been shown that roughen-ing the LED surface can increase the light extraction effi-ciency of nitride-based LEDs. The textured surfaces were obtained by using plasma etching directly on the top layer or on an additional surface layer.

More recently, time-resolved photoluminescence spectros-copy has also been initiated to characterize the materials properties and the effect of the fabrication processes on the materials performance.

UV LEDs emitting below 375 nm are still in their early develop ments and the current efficiencies of such devices is limited. The improvement of these devices requires extensive XRD, AFM and cathodoluminescence analysis to be fed back to the materials growers.

GaN Inductively Coupled Plasma etchingICP etching is a type of reactive ion etching with high den-sity plasma. It allows anisotropic, smooth, non selective and low damage dry etching of AlGaN/GaN heterostructures.

Reference

• “Brightness enhancement of blue light emitting diodes based on AlGaN/GaN heterostructures with ICP etching”, R.F. Leulmi, V. Aimez, R. Arès, G. Huminic and H. Helava, Canadian Conference on Semiconductor technology, Montreal, August 2007.

Available in CRN2 laboratories, the ICP system used for this work is using chlorine chemistries to form high resolution mesa structures with high quality contact strategies as illustrated in Figure 2.

Blue and UV LEDs fabricationThis work will improve LED efficiency (lumen/Watt), as well as the Lumen/$ ratio, with a big potential for industrial ex-change via the collaboration with the Fox Group Inc.

Our goal is to keep the fabrication process simple and therefore at low cost. It is focused on the improvement of contact geometries and interfaces.

Preliminary results demonstrate more than 20% emitting efficiency improvement without any change to the material structure with interdigitated mesa LEDs with respect to stan-dard devices. Further improvements are underway based on new contact strategies and surface roughening scenarios.

Figure 1. Blue LED dies under test

Figure 2. SEM image of AlGaN/GaN-based LEDs with different mesa structures

High lumen/watt blue and UV light emitting diodes based on AlGaN/GaN heterostructures using inductively coupled plasma etching


Atomic Force Microscopy, in combination with single molecular fluorescence techniques, is a powerful tool to study many problems in biology. How interaction forces on the molecular scale to the macroscopic or cellular level can be directly visualized and quantified by combining AFM, various optical techniques and biochemical methods. AFM has been used to image biomolecular processes at the molecular level, determine viscoeleastic properties of smooth muscle cells relevant for asthma, mechanical property changes during synapse formation as well as photophysical properties of semiconductor quantum dots. This facility is operated as a user facility where we provide the instrumentation expertise and projects are defined in collaboration with researchers in the life sciences.

Researchers: Peter Grütter, Hélène Bourque, Paul Wiseman and Robert Bruce LennoxCollaborators: Y. de Koninck (U. Laval); J. Martin (Meakins Christie Labs); J. Dent (U. McGill); E. Shoubridge (Montreal Neurological Inst.); H. Sleiman (U. McGill)Students: Nela Durisic and Fernando SuarezContact: Peter Grütter; [email protected]; www.physics.mcgill.ca/spm

The AFM Facility for the Life Sciences is optimized for AFM applications in the life sciences by combining AFM with single photon fluorescence optical methods and elec-trophysiological measurements using patch clamp tech-niques. The facility is compatible with operation in solution under temperature control with exchange of drugs (home built temperature controlled profusion cell), allowing ex-periments to be performed in-vitro on live, cultured cells. Examples of current research include the investigation of (i) tethering strategies to attach ligands to AFM tips, (ii) cooperative effects of proteins on DNA folding (see fig-ure 1), (iii) viscoelastic properties of smooth muscle cells the associated changes upon various drug treatments, (iv) effects of the substrate mechanical and chemical proper-ties on the mechanical properties and gene expression of culture smooth muscle cells, (v) observation of changes in mechanical properties upon synapse formation in cultured rat neurons (Figure 1), (vi) issues related to the blinking of semiconductor quantum dots and their use as reporters of cellular trafficking or (vii) photophysical effects due to variations of pH and (viii) FRET studies of channel proteins in C.elegans. Projects are typically undertaken in collabora-tion with leading research groups in the life sciences, often making it necessary to customize sub systems of the facil-ity (see e.g. the development of planar patch clamp chips to enable to combination of AFM, fluorescence microscopy

Figure 1. Compaction of circular and linear DNA by the mammalian mitochondrial protein TFAM, 200 nm x 200 nm nc-AFM image (left). Mechanical properties of neuronal synapses at various stages of formation (middle and right). Middle: AFM topography, right: elasticity map

References

• “Dendritic Spine Viscoelasticity and Soft-Glassy Nature: Balancing Dynamic Remodeling with Structural Stability”, B.A. Smith, H. Roy, P. De Koninck, P. Grutter and Y. De Koninck, Biophys. J 92, 1419 (2007).

• “The Mitochondrial Transcription Factor TFAM Coordinates the Assembly of Multiple DNA Molecules into Nucleoid-like Structures”, B. Kaufman, N. Durisic, J. Mativetsky, S. Costantino, M. Hancock, P. Grutter and E. Shoubridge, Mol. Biol. Cell. 18, 3225 (2007).

• “Detection and Correction of Blinking Bias in Image Correlation Transport Measurements of Quantum Dot Tagged Macromolecules”, N. Durisic, A.I. Bachir, D.L. Kolin, B. Hebert, B.C. Lagerholm, P. Grutter and P.W. Wiseman, Biophys. J 93, 1338 (2007).

• “DNA-Protein Non-Covalent Crosslinking: Ruthenium Dipyridophenazine Biotin Complex for the Assembly of Proteins and Gold Nanoparticles on DNA Templates”, M. Slim, N. Durisic, P. Grutter and H. Sleiman, Chem.Bio.Chem. 7, 804 (2007).

• “Probing the Viscoelastic Structure of Cultured Airway Smooth Muscle Cells with AFM: MLCK-Independent Stiffening Induced by Contractile Agonist”, B.A. Smith, B. Tolloczko, J.G. Martin and P. Grutter, Biophys. J 80, 2994 (2005).

Figure 2. DI Bioscope AFM on inverted optical microscope. This system is operated as a user facility.

using a home built total internal reflection fluorescence (TIRF) illumination with 5 wavelengths, a camera capable of single photon detection and patch clamp measurements on single channels (see Figure 2).

AFM for the life sciences: Neurons, smooth muscle cells and blinking q-dots


Micromechanical cantilevers are a new and rapidly developing type of sensor. One of the applications of microcantilevers is to detect small quantities of biochemical molecules by mechanical deflection of a cantilever upon binding to its gold coated and chemically functionalized surface. The size of deflection depends on the cleanliness of the microcantilever surface. We have developed a microcantilever system integrated with electrochemistry for cleaning and characterizing the sensor surface.

Researchers: Peter Grütter, Hélène Bourque, Yoshihiko Nagai and Robert Bruce LennoxCollaborators: R. Sladek (Genome Quebec & Genomics, McGill); J. White (Physiology, McGill)Students: Tanya Monga, Vincent Tabard-Cossa and Michel Godin Contact: Peter Grütter; [email protected]; www.physics.mcgill.ca/spm

The design, fabrication, and implementation of sensors is of great importance to both fundamental research (sensors-as-tools) and clinical research (sensors-as-diagnostic plat-forms). Microcantilever-based sensors have attracted con-siderable attention as a label-free approach for detecting chemical and biomolecular reactions via deflection sensing. A major aspect of our research program involves optimizing the sensor signal, its reproducibility and stability as well as understanding the maximum signals achievable.

We have built cantilever based sensor systems operating in gas, liquid and full electrochemical controlled environments. The latter has the advantage of allowing in-situ cleaning and characterization of the sensor receptor surface. In addi tion, it provides for an extra ‘control button’ to change experi-mental conditions and can be used to perform actuator (in contrast to sensor) experiments. With these systems we investigate the stress evolution during alkanethiol self- assembly and discovered Au(111) grain size dependent kinetic trapping of the lying down phase. This observa-tion could explain the many quantitative discrepancies in measurements of properties of alkanethiols founding the literature. We have furthermore investigated the aging of polypyrrole actuators used as ‘artificial’ muscles and found delamination to be a major failure mechanism. Finally, we have increased the surface stress due to hybridization of complementary DNA strands by a facto of 10-100 as com-pared to the literature. This allows us to potentially build

References

• “Microcantilever-Based Sensors: Effect of Morphology, Adhesion, and Cleanliness of the Sensing Surface on Surface Stress”, V. Tabard-Cossa, M. Godin, I. Burgess, T. Monga, R.B. Lennox and P. Grütter, Anal Chem. Oct 3; 17914755 (2007).

• “Calibrating Laser Beam Deflection Systems for Use in Atomic Force Microscopes and Cantilever Sensors”, L.Y. Beaulieu, M. Godin, O. Laroche, V. Tabard-Cossa and P. Grütter, Appl. Phys. Lett. 88, 083108 (2006).

• “Redox-Induced Surface Stress of Polypyrrole-Based Actuators”, V. Tabard-Cossa, M. Godin, P. Grütter, I Burgess and R.B. Lennox, J. Phys. Chem. B 109, 17531 (2005).

• “Surface Stress, Kinetics and Structure of Alkanethiol Self-Assembled Monolayer”, M. Godin, P. Williams, O. Laroche, V. Tabard-Cossa, L. Beaulieu, R.B. Lennox and P. Grütter, Langmuir 20, 7090 (2004).

powerful DNA and other biomolecular sensors as well as investigating the noise and kinetic limits of established gene chip technologies.

Biochemical recognition on suitably functionalized micromachined cantilevers leads to a detectable signal due to induced stress.

Stress evolution during single stranded DNA absorption on Au coated microcantile-vr (red curve) and hybridization with perfect matchng target (green curve). The two reactions are well described by a Langmuir adsorption kinetics (black fi to data).

Micromechanical biochemical sensors


The evolution of systems driven outside of thermodynamic equilibrium is characterized by strong nonlinearity and the formation of complex spatio-temporal patterns. We conduct theoretical and computational research in this field, including the development of mathematical tools used in the description of these phenomena, and several applications in condensed matter physics, fluid mechanics, and materials science.

Researcher: Jorge ViñalsStudents: Adriano Ferrari, Mathieu Gaudreault, Françoise Lepine and Xusheng ZhangContact: Jorge Viñals; [email protected]; www.physics.mcgill.ca/~vinals

Our research is of theoretical and computational nature, and focuses on nonequilibrium phenomena in extended sys-tems, and in applications of Statistical Mechanics to prob-lems in Biophysics or Biomaterials. In the former case, we aim at understanding the mechanisms underlying the for-mation and evolution of spatio temporal patterns in systems driven outside of thermodynamic equilibrium, including the transition to spatio temporal chaos in extended systems. We focus on prototypical systems and related experimental configurations in which to address fundamental issues of nonlinear phenomena, as well as on configurations of inter-est because of their applications

Block copolymers as a structured materialBlock copolymers are being extensively investigated as nanoscale templates for a wide variety of applications that include nanolithography, photonic components, or high density storage systems. However, given the small wave-length of the microphases (tens or hundreds of Angstroms), macroscopic size samples do not completely order through spontaneous self assembly. Instead, oscillatory shears are commonly introduced in order to accelerate long range order development over the required distances. A meso-scopic model of a diblock copolymer is used to study the formation, stability, and coarsening of lamellar phases, including their hydrodynamic response to applied external shears. The focus of our research is on mechanisms con-trolling long ranged orientational order, including the motion of grain boundaries or other topological defects, and the introduction of a mesoscopic theory of viscoelasticity that can describe the stability and response of these materials to shears, and account for the selection of particular orien-tations depending on the architecture of the block and the parameters of the shear.

Protein-protein interactionsSequencing of the genomes of several species (including humans) opens the door to a new understanding of bio-logical function, as well as to the possible elucidation of the genetic mechanisms of many diseases, and perhaps to their cure through genetic manipulation. This research aims at improving current computational methods that predict the three dimensional structure of proteins and of protein-protein interactions from the knowledge of their amino acid sequence. Protein function is more closely related to structure than to sequence, and hence methodologies that

References

• “Stability of parallel/perpendicular domain boundaries in lamellar block copolymers under oscillatory shear”, Z.-F. Huang and J. Vinals, J. Rheol. 51, 99 (2007).

• “Structural rheology of microphase separated diblock copolymers”, R. Tamate, K. Yamada, J. Vinals and T. Ohta, J. Phys. Soc. Jpn. 73, 034802 (2008).

can produce large scale predictions of protein structure are essential in this post-genomic era. Reduced, lattice based models of proteins, and Monte Carlo simulation methods are used to analyze the relationship between sequence and characteristic structural motifs of the folded protein. Sta-tistical methods are being developed to increase sensitiv-ity in the detection of functional sites and to calculate the thermodynamics parameters that describe protein-protein interactions (formation of dimers, trimers, etc.).

Topological defect motion in modulated phasesModulated phases are ubiquitous in Nature generally resulting in systems with competing attractive interactions at short distances, and long range repulsion. They are gen-erally characterized by some degree of broken symmetry that is intermediate between fully ordered crystals and completely disordered fluids. We consider general order parameter models that are appropriate for a coarse grained description of modulated phases to address a number of generic non equilibrium features, including slow relaxation accompanying topological defect motion, the breakdown of continuum laws of defect motion and the formation of structural glasses, and their dependence on the symmetry of the phases.

Examples of models develop in our lab. Left: Block copolymer and right: dimer of protein GCN4.

Pattern formation outside of equilibrium


We couple the hydrodynamic motion of inks during the printing process to the detailed microscopic structure of a paper sheet in order to predict its print quality. We focus on papers with a high content of mineral fillers, which require less wood fibers and less energy to manufacture.

Ink-paper interaction for papers with high mineral content

Researchers: Martin Dubé and François DroletCollaborators: Patrice Mangin (CIPP, Trois-Rivières) and Jean-Francis Bloch (INP Grenoble)Contact: Martin Dubé; [email protected]; www.uqtr.ca/~dubma

The paper industry is currently transforming itself, shift-ing away from traditional newsprint-type papers towards high value-added papers, such as bioactive or intelligent papers. Another possibility is the development of papers having a high content of minerals fillers, such as clay or calcium carbonate. The manufacturing of these papers requires significantly less wood fibers and energy than traditional grades. It is however a challenge to produce highly filled papers (with up to 50% mineral content in mass) while keeping the mechanical strength and print quality potential of the paper intact.

Print quality is a fundamental attribute of printing papers. However, since it is mostly based on the visual percep-tion and interpretation of human observers, it is not easily defined or measured. There exists several empirical mod-els and descriptions of print quality, but as yet, there exists no platform that can directly predict the influence of pa-per structure (including mineral fillers and surface strength agents) on print quality. To reach this goal, it is necessary to first develop a detailed understanding of ink-paper interac-tions and how they affect print quality.

In recent years, we have developed a continuum model that couples the hydrodynamic motion of a fluid during the printing process to the paper structure. The paper struc-ture can be obtained from numerical simulations or it can be direc tly measured through X-ray microtomography. Already, simulations of ink transfer to simple model sub-strates show a large influence of the pore structure on the transfer process: at constant porosity, there is more trans-fer into small pores than into larger ones, in part due to the increase in capillary forces.

In the future, we will focus on the inkjet printing process and study how an ink droplet placed upon the paper surface spreads and penetrates into the structure. This is illustrated on the accompanying figure, which shows the final configu-ration of a droplet (of picoliter-range volume) initially depos-ited on the paper surface. We will study how the flow of a fluid drop near the surface of a paper is affected by factors such as • the amount of filler in the sheet, and the uniformity of its

distribution • the surface energy of the fibers and of the filler particles• the degree of calendering (which affects surface rough-

ness and porosity) of the sheet

References

• Drolet F. and Uesaka, Advances in Paper Science and Technology: 13th fundamental research symposium, Cambridge, 11-16 Sept. 2005, edited by S.J. I’Anson, vol. 2, pp 1139-1154

• “Fundamental Questions on Print Quality”, P. Mangin and M. Dubé, Image Quality and System Performance III, Luke C. Cui; Yoichi Miyake, Editors, Proceedings Vol. 6059, 605901 (2006).

• “Hydrodynamics of Fluid Transfer”, M. Dubé, F. Drolet, C. Daneault and P. Mangin, accepted for publication, Journal of Pulp and Paper Science (2008).

Simulated structures having different densities and filler dis-tributions will be used in our study. Paper structures recon-structed from X-ray tomography images may also be used. The effect of sizing agents (which modify the wetting prop-erties of the fibers) will be modeled through a local modi-fication of the fibers’ wetting properties. Print quality will be assessed through a measure of the final ink distribution within the sheet (dot gain, dot roundness, proportion of ink on the surface…). The spreading and penetration of several droplets can also be simulated, allowing us to assess print quality through the whole range of tone reproduction.


technological PRoPeRties oF MateRials

As materials sizes are reduced, thermally-induced phase transformations and interfacial reactions become increasingly sensitive to dimensions and materials nanostructure. For example, nucleation-controlled reactions become increasingly difficult to initiate when very limited amounts of materials are involved. The microelectronics industry currently faces such challenges, in particular for the formation of silicide contacts in field effect transistors.

Silicides and germanides for next generation electronic circuits: Novel reaction pathways and crystalline texture evolution

Researchers: Patrick Desjardins, François Schiettekatte and Sjoerd RoordaCollaborators: C. Lavoie, F.M. d’Heurle (IBM Research, United States); C. Detavernier (Universiteit Gent, Belgium)Students: C. Coia, S. Gaudet, M. Tremblay, M. Guihard and P. Turcotte-TremblayContact: Patrick Desjardins; [email protected]; http://desjardins.phys.polymtl.ca

In close collaboration with IBM Research and Universiteit Gent, we investigate the effect of size, nanostructure, and texture (the distribution of the crystallographic orientations of the various grains in polycrystalline materials) of thin films on the mechanisms and kinetics of solid-state reac-tions. We focus on silicides and germanides because of their importance as zero-level interconnection materials in complementary metal-oxide semiconductor microelectro-nics technology (Figure 1).

Using intense synchrotron x-ray beams, we monitor thin film reactions in situ during thermal treatments (Figure 2). Such measurements reveal not only that thin films reactions are significantly modified in nanometer-thick layers, they also highlight new behaviors such as the simultaneous growth of several phases in a thin film system.

Texture evolutionIn the smallest transistors made today, polycrystalline sili-cide contacts comprise only a few grains. Such materials cannot be considered as isotropic polycrystalline materials; controlling texture during film deposition as well as upon subsequent treatments thus become of primary impor-tance. We investigate the impact of the interplay between texture and kinetics during solid state reactions on the mor-phology, stress state, and stability of nanoscale structures. A typical pole figure exhibiting strong axiotaxy (alignment of crystalline planes at the interface) in a NiSi layer on Si(001) is presented in Figure 3.

GermanidesThe replacement of SiO2 as the preferred gate insulator in MOSFET devices by new high-dielectric constant materials

References

• “Reaction of thin Ni films with Ge: Phase formation and texture”, S. Gaudet, C. Detavernier, C. Lavoie and P. Desjardins, J. Appl. Phys. 100, 34306 (2006).

• “Thin film reaction of transition metals with germanium”, S. Gaudet, C. Detavernier, A. Kellock, P. Desjardins and C. Lavoie, J. Vac. Sci. Technol. A 24, 474 (2006).

required for the continued scaling of device dimensions has for consequence to eliminate one of the strongest advan-tages of silicon as the active material, its remarkable oxide not being used as the gate insulator anymore. A variety of alternate semiconducting materials exhibiting higher mobi-lities thus become appealing alternatives for replacing the silicon active region. Because of its higher carrier mobili-ties and relative compatibility with silicon processing, Ge is often proposed as a potential alternative.

We have carried out a systematic investigation of the ther-mally-induced reaction of 20 transition metals with Ge sub-strates in order to identify appropriate contact materials in Ge-based microelectronic circuits. Combining in situ x-ray diffraction, diffuse light scattering, and resistance measure-ments, we have determined the phase formation sequence for each metal-Ge combination. We found that Fe, Co, Ni, Pd, Pt, and Cu were the most interesting candidates for micro electronics applications as they reacted at relatively low temperatures to form low resistivity phases. Among those, two mono-germanides, NiGe and PdGe, exhibited the lowest resistivity (22-30 μΩ-cm) and were stable over the widest temperature window during ramp anneals.

Figure 1. State-of-the-art field-effect-transistor observed in cross-section

Figure 3. Pole figure exhibiting axiotaxy as depicted by circles around specific zone axes

Figure 2. Synchrotron x-ray diffraction curves measured in situ during the ramp anneal of a 10 nm Ni film on Si(001). Highest intensities are indicated in red.

84 | RQMP | PRojects | technological PRoPeRties oF MateRials

Optical coherence tomography is a new noninvasive imaging technology which makes use of broad-spectrum optical sources. In addition to providing structural images, it can yield highly accurate fluid flow velocities using the Doppler effect. It is a very promising technique for microfluidics.

Doppler imaging with optical coherence tomography: Medical and microfluidic applications

Researchers: Romain Maciejko, Olivier Guenat and Lionel CarrionCollaborators: G. Lamouche (IMI); L. Chen (U. McGill); M Piché (U. Laval); J. Azana (INRS-EMT)Students: Z. Xu and M-M. LanthierContact: Romain Maciejko; [email protected]; http//maxwell.phys.polymtl.ca

Optical Coherence Tomography (OCT) is a new technology that appeared about fifteen years ago. In some aspects, it is quite similar to ultrasound imaging but achieves a much higher resolution, of the order of a few microns in the usual configurations. It can provide real-time three-dimensional images in a noninvasive way. In order to obtain a high reso-lution, one must develop optical sources with a very broad spectrum which we did in collaboration with McGill Univer-sity researchers by combining semiconductor optical am-plifiers together with an erbium-doped fiber amplifier thus achieving a 125 nanometer spectrum at a low cost. Thanks to this source and other sources available in our laboratory such as a Ti:sapphire 10 femtosecond laser, we were able to produce numerous images of biological tissues as illus-trated in the following figure.

Our research in this area is ongoing and we are now in the process of comparing OCT images with those obtained by X-rays, ultrasound and magnetic resonance imaging (MRI).

Doppler Imaging In addition to providing structural images, optical coher-ence tomography offers many new possibilities as that, for instance, of measuring liquid flow velocities with an unprecedented resolution. The technique relies on acquir-ing the fringe pattern or the so-called interferogram obtained by combining the light reflected off a continuously moving reference mirror and the light backscattered by the sample under test via a Michelson interferometer often built with optical fibers. If the sample itself is in motion as in the case of a flowing fluid, an appropriate analysis of the interferogram yields the local Doppler frequency which is directly related to the velocity of the sample. Since this type of research is still in its infancy, we have applied Doppler OCT to well documented classical cases such as the flow in a rectilinear cylindrical tube and we have confirmed the accuracy of the method in comparison with theoretical results. A few methods have been proposed to extract the

References

• “A zero-crossing detection method applied to Doppler OCT”, Z. Xu, L. Carrion and R. Maciejko, Optics Express 16, 4394 (2008).

• “An assessment of the Wigner distribution method in Doppler OCT”, Z. Xu, L. Carrion and R. Maciejko, Optics Express 15, 14738 (2007).

• “Novel S+C+L Broadband Source based on Semiconductor Optical Amplifiers and Erbium Doped Fiber for Optical Coherence Tomography”, D. Beitel, L. Carrion, K.L. Lee, A. Jain, L.R. Chen, R. Maciejko and A. Nirmalathas, CLEO 2007; see also Jour. Spec. Top. Quantum Electron. 14, 243 (2008).

Doppler signal from the interferogram and we have recently shown that the analysis based on the de Wigner-Ville func-tion gave an increased accuracy. In order to improve on the data processing speed, we have come up with yet another approach based on a zero-crossing technique which reduced substantially the processing time and kept accuracy high. Afterwards, we have applied the method to the study of fluid flow in tubes with tapered regions, simu-lating stenoses in a blood vessel.

MicrofluidicsGiven the increased resolution and accuracy of OCT Doppler imaging, it appeared quite natural to apply this technique for imaging the flow of liquids in micro-circuits designed for biological analyses in the context of labs-on–a-chip. Since the scale of the channels is of the order of 100 microns to a few millimeters, the technique we have developed is highly suitable. So far, we have successfully imaged a number of microfluidic circuits and research is being pursued on ever more complex structures.

OCT image of chicken cardiac tissue.

Profile of Doppler frequencies for the flow in a rectilinear tube


A capacitive micro-accelerometer was designed and fabricated for structural health monitoring of aircraft. In this research, the vibration-based sensing scheme is employed in order to determine the existence of structural damage and localise the defects utilizing changes in the global dynamic response. Since working at its own resonant frequency, the device gives not only high selectivity but also high sensitivity. The accelerometer was fabricated using CMOS compatible silicon micromachining technology. Mechanical properties of the fabricated micro-accelerometer such as a spring constant and a damping coefficient of the system were extracted from electrical measurements. This project is in collaboration with Bombardier.

Researchers: Michel Meunier and Yves-Alain PeterCollaborators: Patrice Masson and Philippe Micheau (U. Sherbrooke)Postdoctoral fellow: In-Hyouk SongContact: Yves-Alain Peter; [email protected]; www.polymtl.ca/mems/

Structural health monitoring (SHM) systems are currently being developed for reducing the high costs associated with periodic prescribed inspections of aircraft structures. To de-termine the existence of structural damage and localise the defects, a global dynamic response on the overall structure is performed from modal analysis. Microelectromechanical systems (MEMS) technology has been studied as a can-didate for fabricating SHM systems. We have designed a capacitive type micro-accelerometer to monitor variations in the resonant frequency of the structure by measuring the changes in capacitance of the sensor.

In this research, the vibration-based SHM system is designed and fabricated. The proposed micro-SHM sen-sor is a resonant frequency sensitive micro-accelerometer, which is designed having an identical resonant frequency with that of monitoring structure. The device is working at its own resonant frequency. Hence, it gives not only high selectivity but also high sensitivity since the displacement of moving structure is maximized at resonant frequency for a given acceleration. The working distance of the resonat-ing proof mass is 5 mm. Figure 1 shows the capacitance changes with respect to the proof mass displacement. At 3 mm displacement, the capacitance is shifted from the ini-tial capacitance by 1.084 pF.

Reference

• “Smart Technologies for Structural Health Monitoring of Aerospace Structures”, P. Masson, P. Micheau, Y. Pasco, M. Thomas, V. Brailovski, M. Meunier, Y.-A. Peter, In-hyouk Song, D. Mateescu, A. Misra, N. Mrad, J. Pinsonnault, A. Cambron, International Workshop on Smart Materials and Smart Structures

(Cansmart 2006), 191, 26 Oct. 2006, Toronto, Canada.

CMOS compatible micromachining process was utilized to fabricate the capacitive micro-accelerometer on a silicon-on-insulator (SOI) wafer. Figure 2 shows the scanning elec-tron microscopy (SEM) photograph of a fabricated micro-accelerometer. The thickness of the moving structure is 80 mm released from the handle layer with a 3 mm thick air gap.

The mechanical properties of the fabricated device were tested and electrically characterized. The viscous damp-ing ratio of the system, x = 0.189 has been obtained. The spring constant and damping coefficient were estimated to be 24.75 N/m and 6.7 x 10-4 N.s/m, respectively, using the undamped resonant frequency of 2.2 kHz. More work are being performed on the device optimisation and its intergra-tion in aircraft SHM systems.

The authors acknowledge the financial contributions from CRIAQ (Consortium for Research and Innovation in Aero-space in Quebec).

Figure 1. Capacitance change versus proof mass displacement.

Figure 2. SEM photograph of the fabricated micro-accelerometer on SOI wafer.

Micro-accelerometer for structural health monitoring of aircrafts


Main goal of this research is to design, fabricate and test new nanostructured materials and coating systems providing enhanced performance by a combination of excellent mechanical, tribological and corrosion characteristics leading to significant enhancement in performance of the components and systems used in aerospace and avionics, automobile and transport, manufacturing and other sectors. Finite element modeling based methodology was developed to simulate coating response to impact load exerted by eroding particles.

Researchers: Jolanta E. Klemberg-Sapieha and Ludvik MartinuCollaborators: J. Szpunar (U. McGill); F. Gitzhofer (U. Sherbrooke); O. Zabeida (Polytechnique); M. Bielawski (NRC); A. Raveh (Israel)Students: E. Bousser, S. Hassani, M. Hala, G. Srinivasan, P. Robin, M. Benkahoul, M. Azzi and D. LiContact: Jolanta Klemberg-Sapieha; [email protected]; www.polymtl.ca/larfis

Erosion characteristics are very critical to safe and optimum performance of different parts on aircraft engines and heli-copters. Components such as compressor blades, discs on engines and leading edges of helicopter blades are among such parts that have to operate in hostile environments. Titanium-, nickel- alloys and stainless steel materials are often used in compressor blades for their high strength-to-weight ratio and good resistance to creep and fatigue. However, the main problem is their low resistance to par-ticulate erosion, wear, fretting and corrosion, leading to the deterioration of their aerodynamic performance, excessive vibration and possible catastrophic failure.

In response to these urgent needs and based on under-standing the complex tribo-mechanical properties, this research team is developing new coating architectures including multi-layer, graded layer and/or nanostructured coatings and coating systems, which combine controlled hardness and elastic modulus, high toughness and adhe-sion, and that correspond to specific industrial needs.

Essential part of the project is the design and fabrication of such systems that include hard and superhard coatings as well as a combination of amorphous, polycrystalline and nanocomposite layers.

It was shown that nanocomposite films formed by metal nitride, metal carbide or metal carbon-nitride particles (5 -10 nm in size) imbedded in an amorphous matrix give rise to superhardness (H > 40 GPa) and very high tough-

References

• “Quaternary Hard Nanocomposite TiCxNy / SiCN Coatings Prepared by PECVD”, P. Jedrzejowski, J.E. Klemberg-Sapieha and L. Martinu, Thin Solid Films 466, 189 (2004).

• “Real-Time In-Situ Growth Study of TiN- and TiCxNy- Based Superhard Nanocomposite Coatings Using Spectroscopic Ellipsometry”, P. Jedrzejowski, A. Amassian, E. Bousser, J.E. Klemberg-Sapieha and L. Martinu, Appl. Phys. Lett. 88, 071915 (2006).

ness. These properties are now being explored for imple-mentation in multilayer and graded layer architectures suitable for their use on compressor blades of jet engines, components of helicopters and aircrafts, medical implants and instrumentation.

Special effort is devoted to the design of coating architec-tures, study the erosion mechanisms and to predict the coating behavior in simulated erosion conditions using finite element methods, FEM.

We have developed and validated a single particle erosion model using FEM. This method has then been used for the prediction of the erosion rate of multilayer systems consist-ing of nanocomposite films. Fabrication and testing of coat-ings and comparisons with FEM are in progress.

Structural evolution of nanocomposite material.

Area of high probability of crack formation.

Advanced erosion and tribo-corrosion resistant coatings


The main aim of this research project is to develop advanced thin film optical filters employing multilayer and graded layer architectures. It focuses on new optical design methods, new fabrication and process control and monitoring approaches, reverse engineering techniques and new materials, with a goal to obtain filters with optimized spectral characteristics, mechanical performance and environmental stability. Main results include development of an open-source optical design software, optical filters for security, sensors and astronomy, and optical coatings on plastic substrates.

Researchers: Ludvik Martinu, Jolanta E. Klemberg-Sapieha and Subhash GujrathiCollaborators: C. Carignan (U. Montreal); O. Zabeida (Polytechnique)Students and Post-docs: A. Amassian, S. Larouche, B. Baloukas, M.-M. De Denus-Baillargeon, R. Vernhes, H. Szymanowski, M. Dudek and O. HernandezContact: Ludvik Martinu; [email protected]; www.polymtl.ca/larfis

Advanced thin film optical interference filters (OIFs) are becoming increasingly important in various areas ranging from optics, optoelectronics and telecommunication to high precision instrumentation such as in astronomy, security devices, energy conversion, displays and others. Industrial-ly, this represents a worldwide market between 4 and 5 bil-lion USD/year, while new challenges and opportunities are seen in new processes and fabrication technologies, which provide high quality devices combining well-controlled opti-cal performance, reliable mechanical integrity and high long term environmental stability.

In this respect, our Functional Coating and Surface Engi-neering Laboratory (FCSEL, or LaRFIS) particularly focuses on the following areas:

a) New concepts of optical filters using novel design techniques applied to graded-index and inhomogeneous optical filters [1]. Due to the lack of availability of other solutions, we have created our own software that allows one to design such inhomogeneous structures, but which also possesses capabilities similar to those of commer-cially available softwares. This can be applied in situations when considering narrow band rejection filters, such as in astronomical devices, designed and preliminarily tested in telescope optical systems.

b) Anti-counterfeiting devicesCounterfeiting and reproduction occasion a loss of about 600 billion US dollars annually worldwide. Stimulated by this need, we have recently proposed and demonstrated the use of metamerism to create hidden images for anti-counterfeiting applications [2]. Metamerism is a property of two objects that show the same color under a given illumi-nant, regardless of the fact that they share or not the same transmission/reflection spectra. It is possible to create a hidden image by applying a simple colored material (ink, paint, …) in a certain region of the substrate and an OIF with the same color, at normal incidence, in other regions. When the substrate is tilted, the color of the OIF-covered region changes, while that of the region covered by the colored material remains unchanged.

References

[1] “Microstructure of Plasma-Deposited SiO2 / TiO2 Optical Films”, S. Larouche, H. Szymanowski, J.E. Klemberg-Sapieha, L. Martinu and S. Gujrathi, J. Vac. Sci. Technol. A 22, 1200 (2004).

[2] “ Use of Metameric Filters for Future Interference Security Images Structures”, B. Baloukas, S. Larouche and L. Martinu, in Proc. Conf. on Optical Security and Counterfeit Deterrence Techniques VI, vol. 6075, R. L. van Renesse, ed., SPIE, San Jose, CA, 2006, p. 381.

[3] “Single Material Inhomogeneous Optical Filters Based on Microstructural Gradients in Plasma Deposited Silicon Nitride”, R. Vernhes, O. Zabeida, J.E. Klemberg-Sapieha and L. Martinu, Applied Optics 43, 97 (2004).

c) Porous/dense OIF systemsPlasma enhanced chemical vapor deposition (PECVD) al-lows one to selectively control the energy and flux of the deposited particles and, therefore, the porosity of the films as well as the size and size-distribution of the pores. Based on this approach, we have developed an original method to fabricate nano-porous Si3N4 - based thin films with a large internal area [3], which can effectively be applied as part of optical (bio)chemical sensors. Using films with various levels of porosity, we initiated to implement such layers in optical thin film sensors.

This project is now being expanded to include OIFs involv-ing active (smart) materials and plastics.

Example of a metameric OIF device.

Nano-structured optical interference coatings


Use of plasma-based interface engineering approaches has been applied for adhesion improvement in the context of two biomedical applications: 1. Nano-structured carbonaceous (diamond-like carbon) tribological film systems on metal substrates, which provide high wear and corrosion resistance, biocompatibility, and tailored electrical properties suitable for implants, prostheses and biomedical instrumentation; 2. Protein-based high-water-content hydrogels on polymeric backings suitable for health care applications ranging from wound dressing, artificial tissues (tendons), in-laboratory reagents for culture or transport media, and biosensor devices to cosmetic applications for hydrating masks.

Interface engineering of materials for biomedical applications

Researchers: Jolanta E. Klemberg-Sapieha, Ludvik Martinu and Subhash GujrathiCollaborators: J. Szpunar (U. McGill); O. Zabeida (Polytechnique); E. Park, K. Taylor and K. Casey (Medtronic); C. Roberges, K. Shingel and M.-P.Faure (Biortificial Gel Technologies Inc.)Students and Post-docs: P. Amirault, M. Azzi, D. Escaich, M. Paquette and R. SnydersContact: Jolanta Klemberg-Sapieha; [email protected]; www.polymtl.ca/larfis

1. Nano-structured diamond-like carbon (DLC) films for biomedical applications In orthopaedic applications, artificial joints, e.g., hip and knee prostheses, include bearing surfaces where the mate-rial is subjected to a sliding wear. In addition, the contacted surfaces are immersed in the body fluid, and therefore cor-rosion may also be a concern. Particles generated from wear of prosthetic implants induce inflammatory reactions that provoke the release of inflammatory mediators from macrophages.

Plasma-deposited DLC films alone or doped on the atomic or nano-particle levels have been investigated due to their potential of attaining a combination of desirable properties.

Major issue for this type of applications is the adhesion between the “hard” DLC coating and the “soft” metallic substrate. We have specifically studied the effect of tailoring the interface between the two components by comparing two duplex approaches: (i) metal surface nitriding in an RF discharge for the reinforcement of metal-DLC bonding prior to DLC deposition, and (ii) fabrication of interfacial layers, the latter one leading to the best performance. In situ real-time tribo-corrosion testing, combining instantaneous wear and corrosion measurements (corrosion current and pitting potential), was performed using reciprocating sliding in Ringer’s solution simulating body-fluid environment. Optimized interfacial layers on both medical-grade stainless steel and titanium alloys allowed the film system to resist the entire tribo-corrosion test without failure. We have shown that the interfacial layer significantly decreased the charge transfer between the substrate and the electrolyte by acting as a corrosion barrier, yielding a value of 2 GW.cm2.

References

• “Tribo-Mechanical Properties of DLC Coatings Deposited on Nitrided Biomedical Stainless Steel”, R. Snyders, E. Bousser, P. Amireault, J.E. Klemberg-Sapieha, E. Park, K. Taylor, K. Casey and L. Martinu, Plasma Process. Polym. 4, S1 (2007).

• “Mechanism of adhesion between protein-based hydrogels and plasma treated polypropylene”, R. Snyders, O. Zabeida, C. Roberges, K.I. Shingel, M.-P. Faure, L. Martinu and J.E. Klemberg-Sapieha, Surface Science, 601, 112 (2007).

2. Adhesion mechanism between protein-based hydrogels (HG) and plasma treated polymerStrong interests in the development of novel synthetic HG can be attributed to their unique combination of properties such as biocompatibility, permeability, hydrophilicity and others. Recently, hybrid HGs based on blends of synthetic and natural polymers, referred to as “bioartificial polymeric materials”, have been successfully developed. The main limitation of HGs with high content of water (up to 96%) is their fragility. Therefore, in order to facilitate their handling and manipulation, they require backing, usually made out of a polymer film, for example, polypropylene (PP).

Using nitrogen-containing plasma treatment of PP, the work of adhesion was found to be 25 times higher com-pared to untreated PP substrate. Chemical derivatiza-tion in conjunction with XPS analyses clearly showed the essential role of primary amine (C-NH2) and amide (N-C = O) groups in the adhesion process between PP/N2 and HG. In addition, detailed dynamic mechanical tests of HG allowed us to reveal the molecular structure and pore size, in order to prepare the environment for HG doping with medica-ments for drug delivery.

Joint replacements.

Application and handling of hydrogel without and with polymer backing.

RQMP is a Strategic Cluster, supported by the “Fonds québécois de la recherche sur la nature et les technologies” (FQRNT)and by Université de Montréal, Université de Sherbrooke, McGill University and École Polytechnique de Montréal.

activity report 2003-2008 · the nature of advanced materials is such that progress . depends...

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