Phonon shifts and widths in dilute elemental semiconducting alloys

Abstract

We have undertaken a detailed low-concentration Green’s-function approach to study the frequency shifts and widths of phonons in dilute elemental semiconducting alloys. The force-constant changes estimated from a tight-binding method along with the corrections caused by the variation in volume due to alloying are properly incorporated in the theory. The calculated results have provided a fair agreement with the inelastic neutron scattering data of phonon shifts for the Ge–9.2 at. % Si system and the theoretical values for other alloys are compared and discussed with the existing optical experiments.