Nonequilibrium Interface Dynamics:
Theory and Simulation from Atomistic to Continuum Scales

CSIC Building (#406), Seminar Room 4122.
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Equilibrium Fluctuations and Evolution of Morphology

Dr. Ellen Williams

Department of Physics, and Institute for Physical Science and Technology, University of Maryland

Abstract:   Atomic mobility on surfaces manifests itself in thermal fluctuations of the step edges. Dynamic measurements of such fluctuations on Si, Pb and Ag surfaces using REM, LEEM and STM techniques will be presented. Given such real-space, real-time data, analysis of the fluctuations is accomplished again by statistical techniques through direct calculation of the temporal correlation functions. Different kinetic mechanisms for the fluctuations yield different signatures in the correlation functions. The extraction of this information and correlated time constants will be presented for several experimental systems.

The combination of energetic information (from equilibrium structures) and kinetic information (from dynamic measurements) allows prediction of the stability and evolution of nanoscale structure. This will be illustrated by for the decay of metastable structures on Si surfaces under thermal equilibration, and under structural evolution due to a driving force induced by bulk electrical current, e.g. a surface electromigration effect.

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