Anisotropic atom diffusion on Si(553)-Au surface

Abstract

Using density functional theory, we study atomic diffusion on the Si(553)-Au surface. We have calculated the potential energy surfaces for atoms of different chemical elements (Ag, Au, Mg, In, and Si). By tracing the adatom positions and the energetics of a fully relaxed surface, we have calculated energy barriers, diffusion paths, and hopping rates along and across the steps. The results show that in most cases, the surface diffusion is strongly anisotropic, while the energy barriers and hopping rates have a strong dependency on the chemical species of the adatom. In the case of Au, Ag, and Mg atoms, the diffusion can be realized in two separate one-dimensional channels, featuring different mechanisms of the diffusion.