New Bond-Charge Model for the Lattice Dynamics of Diamond-Type Semiconductors

Abstract

A new bond-charge model for phonons in semiconductors of diamond structure is presented. I show that the flattening of the transverse acoustic phonon branches in these materials can be understood by interactions involving the bond charges, when these move adiabatically. The phonon spectrum of Ge is calculated using only four parameters, all of which are physically meaningful, and very good agreement with experimental values is obtained.