Theory of self-diffusion at and growth of Al(111)

Abstract

We studied the self-diffusion at clean, flat as well as stepped Al(111) surfaces using density-functional theory. There are two important steps on fcc(111) surfaces, typically labeled according to their {111} and {100} microfacets. We calculated the formation energies of these steps, and analyzed the diffusion perpendicular and parallel to them. We discuss the general profile of the diffusing-atom potential-energy surface and identify the role of ``normal'' hopping and exchange mechanisms of diffusion at steps. From these results the equilibrium shape of islands and the temperature dependence of the island shapes under growth conditions are predicted.