Pattern formation induced during strained growth

Kenneth R. Elder, Oakland University, DMR 0906676

When a material solidifies on the surface of another material with similar crystalline structure, the solidifying material will often attempt to grow coherently with the substrate. Small difference in the structures can however lead to strain induced patterns that may be detrimental or beneficial depending on the technological application. The PI and collaborators have recently developed computational efficient methods for studying a wide variety of such phenomena.

The three figures on the left are simulations of GeSi quantum dot formation on Si nano-ribbons, a processes that has the potential of generating a spatial modulated band gap that would have many applications in the electronic device industry. The three figures on the right show a simulation of the ordering of a thin films of copper on a ruthenium substrate. Such bimetallic surfaces are commonly used to enhance chemical reactions rates which are strongly influenced by the specific spatial patterns the copper layers form.

Formation of quantum dots on a nano-ribbon

Patterning of Cu layers on Ru(0001) substrate

time = t1

t2 > t

1

t3 > t

2

one mono-layer

Si

Si

Si

GeSi

two mono-layers

four mono-layers

(side view) (top view)

Collaborators on award #0906676 Top row: Z-F Huang (Wayne State U), N Provatas, J.J. Hoyt (McMaster U, Canada), E. Granato (INPE,Brazil); Middle row: T Ala-Nisillä, G. Rossi, C. Achim, A. Jaatinen (Aalto U., Finland): Bottom row:S. Mkhonta (U. Swaziland, Swaziland), K. Thornton (U. Michigan), S-C Ying (Brown), M. Grant (McGill, Canada)Missing: D-H Yeon (U. of Michigan), J.A.P. Ramos (INPI, Brazil),D. Dobbins, M. Nazrulla (Oakland U).

The research conducted under this award has had a broad impact in many areas including,

Publications in refereed journals2010: three articles in the Physical Review E, one article in the Physical Review B, two articles in the Philosophical Magazine, one in the Journal of Condensed Matter Physics, and one in the European Journal of Physics E.

International collaborations and visits, •Aalto U., Espoo, Finland, Aug. / Feb. 2010•Heinrich-Heine U. of Düsseldorf, Germany, Aug. 2010•McMaster U., Hamilton, Canada, July 2010 •Hong-Kong Polytechnical U. Hong Kong, June 2010.•Institute of Materials Physics in Space, German Aerospace Center (DLR), Cologne Germany, Sept 2009

Invited lectures at international conferences•2010 International Symposium on Multi-scale Modeling and Simulation of Materials, Shengyang China, July 2010.•PTM 2010, Solid-Solid Phase Transformations in Inorganic Materials, Avignon France, June 2010.•CECAM Conference on Classical Density Functional Theory in Soft and Hard Matter, Lausanne, Switzerland, Oct 2009.•Bridging the Gap Workship, McMaster U, Hamilton, Canada, Oct 2009.•2nd Symposium on Phase-Field Modeling in Materials Science, Aachen Germany, Aug. 2009.

Pattern formation induced during strained growth

Kenneth R. Elder, Oakland University, DMR 0906676