Phonon frequency spectrum in random binary alloys

Abstract

The augmented space formalism of Mookerjee (1973, 1975) is used to develop a cluster CPA formalism for the phonon density of states in random binary alloys. Off-diagonal disorder has been incorporated and a self-consistent medium is generated for the calculations. Unlike earlier work, the Green function does not suffer from analytical difficulties in any concentration range and a correct averaging over random masses is performed. Results for linear chains demonstrate that the self-consistent medium gives superior estimates of the band edges and the structures near them.