Hamburg 2001 – scientific programme

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O: Oberflächenphysik

O 2: Hauptvortrag

O 2.1: Invited Talk

Monday, March 26, 2001, 10:15–11:00, B

Substrate-Mediated Adsorbate Interactions: Quantification and Ramifications for Nanostructures at Surfaces — •Kristen A. Fichthorn — Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802

When two or more atoms bind to a solid surface, the substrate can mediate an interaction between them. In this work, we use density-functional theory to quantify substrate-mediated pair and trio interactions between adatoms on compressively strained and unstrained Ag(111) surfaces. At its strongest, this interaction is repulsive, electronic in origin, and forms a ring-like structure around the adatoms. We calculate energy barriers for adatoms to diffuse in each of these systems and find that repulsive interactions can significantly influence adsorbate diffusion. We use kinetic Monte Carlo simulations to show that these interactions can lead to large island densities and special island shapes during thin-film growth.