Condensed Matter Physics Seminar

Friday, April 16, 1999, 2 p.m.
Plant Sciences Building, Room 1130

Atomic-Scale Modeling of Metallic Surfaces in an Electrochemical Environment

Michael Haftel

(Naval Research Laboratory and University of Maryland)

Abstract: The electrolytic cell provides a potentially powerful means of  manipulating surface features in thin-film growth. Altering the applied potential to the electrolytic solution can radically change the electronic environment on the surfaces of the electrodes.  The computational difficulties of including the effects of a electric field on realistic surfaces with large unit cells has prevented first-principles atomic-scale modeling in the electrochemical environment. A computationally tractable semiempirical approach, based on the embedded-atom-model (EAM), will be presented and applied to predicting, as functions of the electrochemical potential, the reconstructed surface phases of metal electrodes and the diffusion barriers for atoms adsorbed on them. As surface stress greatly influences reconstructions and diffusion barriers in ultra-high-vacuum (UHV), its influence when produced by the  excess  charge present on the surface in the electrolytic double layer is reexamined. While the influence of surface stress on reconstruction and diffusion barriers is found to be similar to that in UHV, important charge-dependent effects not attributable to stress will be described.

Host: Ted Einstein

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