Interface Vibrational Modes in GaAs-AlAs Superlattices

Abstract

We report the observation of interface phonons by Raman scattering from GaAs-AlAs superlattices. These modes have frequencies close to the optical phonons of bulk GaAs and AlAs and resonate strongly for laser energies near the confined exciton levels of the GaAs quantum wells. The results are analyzed in terms of an electrostatic continuum model. In the long-wavelength limit this theory predicts the phonons of the layered media proposed by Merlin et al.