Surface phonons and reconstruction for zincblende structures

Abstract

Using a Green function method the dispersion of surface phonons in ZnS-structure crystals is investigated. Special emphasis is put on a discussion of the influence of short and long range forces. Short range forces are described by a Born-von-Karman-model, long range forces within a dipole model. The different types of forces lead to distinct features in the dispersion curves, especially in connection with soft modes. From the soft modes we conclude the existence of certain surface reconstructions, which again seem to be sensitive to long and short range interactions. More detailed calculations are done for Si and GaAs as the representatives of these crystals.