Raman scattering study of acoustical zone-center gaps in GaAs/AlAs superlattices

Abstract

We present a detailed theoretical analysis of the folded acoustical gaps in superlattices within the framework of the elastic approximation and compare its predictions with both backward and forward Raman scattering experiments. We thereby obtain the first evidence of a zone-center gap between folded acoustical branches and also conclusive proof of the photoelastic nature of the involved light scattering process. A good quantitative description of the experimental results is obtained.