Colloquium, Departimento di Fisica, Universit√° di Genova, Italy, 05/18/05

The Driving Forces of Directed Self-Assembly on Strained Metallic Interfaces

Karsten Pohl

Department of Physics and Materials Science Program, University of New Hampshire, Durham, NH, U.S.A.

The spontaneous formation of organized surface structures at nanometer scales is an elegant way to fabricate nanostructured thin films. To make practical use of self-assembled arrays, however, the factors that control their formation and influence their stability must be understood. We will show how well-ordered networks of misfit dislocations that form in monolayer-high strained metal film can be used as templates to grow two-dimensional nano-arrays of large-scale order and size through a combination of interfacial stress and corrosion.

Unique real-time measurements of the dynamics of self-assembled nano-arrays using a home-built variable-temperature STM and LEEM will be presented. The experiments have identified the driving forces that spontaneously organize nanoscale surface structures and quantified the delicate balance between long-range strain field interactions and short-range chemical forces that stabilizes them.

This work is supported by CAREER award DMR-0134933 from the National Science Foundation.