p. grutter contacting the nanoworld peter grutter physics department mcgill university nserc, fcar,...
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P. Grutter
Contacting the Nanoworld
Peter Grutter
Physics Department
McGill University
NSERC, FCAR, CIAR, McGill, IBM, CIHR, GenomeQuebec, CFI, NanoQuebec
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Molecular electronics: the issues
• Contacts• Structure-function
relationship between transport process and molecular structure
• Dissipation
• Crosstalk (interconnects)
• Architecture • I-O with a trillion
processors• Fault tolerance• Manufacturing costs
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Does atomic structure of the contact matter?
YES !
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Does atomic structure of the contact matter?
Mehrez, Wlasenko, et al., Phys. Rev. B 65, 195419 (2002)
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Comparison of Experimental and Modeling Results
Mehrez, Wlasenko, et al., Phys. Rev. B 65, 195419 (2002)
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Low-T UHV STM/AFM/FIM
140K,
10-11mbar
quick change between
FIM - AFM/STM mode
Stalder, Ph.D. Thesis 1995
Cross et al. PRL 80, 4685 (1998)
Schirmeisen et al. NJP 2, 29.1
(2000)
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Field Ion Microscopy
(FIM)
E. Muller, 1950’s
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FIM of W(111) tip
Imaging at 5.0 kV
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FIM of W(111) tip
Imaging at 5.0 kV
Manipulating at 6.0 kV
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FIM of W(111) tip
Imaging at 5.0 kV
Manipulating at 6.0 kV
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FIM of W(111) tip
Imaging at 5.0 kV
Manipulating at 6.0 kV
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Single Au atom on W(111) tip
Imaged at 2.1 KV
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W(111) tip on Au(111)
Cross et al.
PRL 80, 4685 (1998)
Schirmeisen et al,
NJP 2, 29.1 (2000)
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Molecular Dynamics Simulations
U. Landman et al, Science 248, 454 (1990)
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W(111) trimer tip on Au(111)
Ead = 21 eV
= 0.2 nm
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Tip relaxation effects
Hofer, Fisher, Wolkow and Grutter Phys. Rev. Lett. 87, 236104 (2001)
W tip on Au(111) surface
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Tip relaxation effects
Hofer, Fisher, Wolkow and Grutter Phys. Rev. Lett. 87, 236104 (2001)
W tip on Au(111) surface
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F(z) and I(z) of W(111) trimer on Au(111)
Schirmeisen et al,
NJP 2, 29.1 (2000)
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Yan Sun,
Sarah Burke
Henrik Mortensn
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Self-assembled quantum dots
50 nm diameter InAs Qdots grown on 10 nm InP and a
InGaAs 2DEG
Sample grown at NRC IMS J. Levebvre, P. Poole, R. Williams et al
J. Crystal Growth (2002)
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First results of cryogenic electrostatic force spectroscopy
R. Stomp,
Y. Miyahara
S. Studenkin (NRC)
A. Sachrajda (NRC)
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distance
tip gap 2DEGQdot
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distance
tip gap 2DEGQdot
Force between capacitor plates
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E
distance
tip gap
InP
InPInP
InAs
InGaAs
2DEGQdot
Force between capacitor plates
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E
distance
tip gap
InP
InPInP
InAs
InGaAs
2DEGQdot
Electrical potential applied between tip
and 2DEG
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E
distance
tip gap
InP
InPInP
InAs
InGaAs
2DEGQdot
Electrical potential applied between tip
and 2DEG
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E
distance
tip gap
InP
InPInP
InAs
InGaAs
2DEGQdot
30-50 nm
Electrical potential lever armcan be tuned by:
applied Vtip-sample
tip-sample separationsample structure
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Contacting a nano-dot with a Au wire
M. Pumarol S. Studenkin (NRC IMS)
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Stimulation of Single Ligand-Gated Ion Channels
Natural Process:Synaptic Transmission
Goal: To study channel gating kinetics and binding forces, while maintaining precise control of agonist location.
Experiment: Ligand-functionalized AFM tip
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N. Cameron, B. Lennox (McGill)
Tethering Scheme:GABA v.s. GABOB
• Is it possible to tether a molecule of GABA without destroying its functionality?
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Tethering Scheme: Polymer Linker
Au -S-(CH2)12-(O-CH2-CH2)23-O-GABOB {alkanethiol} {PEO}
Colloid simulates the AFM tip
Keeps the colloid complex soluble (?)
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Planar Patch-Clamp Chips• Advanced microstructuring techniques are used to produce apertures in planar glass or quartz substrates.• Low noise recordings have been realized from both artificial lipid bilayers and whole cells.
Fertig et. al. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2001 Oct;64(4-1):040901.
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F(z) as a function of
pulling speed
Clausen-Schaumann et al., Current Opinions in Chem. Biol. 4, 524 (2000)
Merkel et al., Nature 397, (1999)
Allows the determination ofenergy barriers and thus is a direct measure of the energy landscape in conformational space.
Evans, Annu. Rev. Biophys. Biomol. Struct., 30, 105 (2001)
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Loading Rate Dependent Unbinding:
Most probable unbinding force:
• Ligand-receptor dissociation forces and rates depend on the rate at which the bond is ruptured!!!• Distinct binding states can be identified from a force v.s. loading rate plot.
Good review: Evans, E. Annu. Rev. Biophys. Biomol. Struct. 2001. 30:105-28.
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Summary
• Tools, both experimental and theoretical, drive our capabilities to understand the nanoworld!
• We develop and apply SPM techniques to interface to:
1. Molecules
2. Quantum dots
3. Neurons
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Supported by
NSERC, FCAR, CIAR, NanoQuebec
CFI, IBM, GenomeQuebec, CIHR
McGill Dawson Scholarship
14 graduate students, 6 post doctoral fellows
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