Phonons in Si3Ge1 and Si1Ge3 short-period superlattices

Oscillatory spectra and single-phonon state densities are calculated in the Keating atomic interaction model for the ultrathin superlattices Si₃Ge₁ and Si₁Ge₃. Fundamental features of the superlattice phonon spectra and their relationship to the spectra of Si and Ge crystals are analyzed. Conditions required for oscillation localization in the interface region are studied and the role of the Si-Ge bond in formation of interlayer oscillations is considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii. Fizika, No. 8, pp. 40–44, August, 1993.