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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