Band structure effects in the surface plasmon at the Be(0001) surface

Abstract

Surface collective charge excitations are investigated for Be(0001) surface with explicit inclusion of band structure effects evaluated within an ab initio pseudopotential approach. The strong impact of beryllium surface band structure on the collective excitations at this surface is shown. Instead of a single-peak structure in the surface loss function following from a free-electron gas model, a structure consisting of two almost non-dispersing peaks is obtained in ab intitio calculations. A study of the comparative roles of surface band structure and dynamical exchange correlations on the surface collective excitations dispersion shows that the main effect comes from the three-dimensional band structure, although exchange-correlation effects have certain importance for large two-dimensional momenta.