Phonon Dispersion Curves of BeSe and BeTe

Abstract

The purpose of our study is to calculate the phonon dispersion curves of BeSe and BeTe. Owing to the few available data, a simple model demanding only a reduced set of force constant-parameters is required. A well-adapted model is the one of De Launay (Solid State Phys. 3, 203 (1957)) based on atomic central and angular forces. The model has been implemented by introducing the polarization field into the dynamical equations for the longitudinal modes.