First-principles screening calculation of the surface phonon dispersion curves at the (100) surface of sodium

Abstract

A self-consistent nonperturbative screening calculation of the phonon dispersion relations for sodium has been carried out for both the bulk and the (100) surface. The static density response function for the electrons was calculated self-consistently from the solutions to the single-particle Kohn-Sham equations in the local density approximation with the bare ion-electron interaction taken to be a local Heine-Abarenkov pseudopotential. The dynamical matrix was calculated from the response function and diagonalized to yield the normal mode frequencies and eigenvectors. For the surface problem a crystal slab bounded by (100) surfaces and containing 13 atomic layers was employed.