Surface atomic and electronic structure of cassiteriteSnO2(110)

Abstract

Using a tight-binding, total-energy model, we have calculated relaxed surface atomic positions, surface-state energies, and densities of states for the reduced and stoichiometric (110) surfaces of rutile-structure tin dioxide (cassiterite). Both relaxed surfaces display a small rumple of the top atomic layer and smaller counter-rumples of the subsurface layers. The surface-state energy lowering caused by the relaxation is small because of the surface topology, which forbids bond-length-conserving motions of the surface atoms. The density of states for the reduced surface agrees qualitatively with photoemission data that indicate the absence of surface states in the fundamental gap of the material.