Raman Scattering from Magnetoplasma Waves in Semiconductors

Abstract

A general theory has been developed for Raman scattering from magnetoplasma waves in semiconductors with arbitrary band structure. The method used is an extension of that previously developed to explain the mixed plasmon-phonon scattering in GaAs. We assume that (1) the excitation of the magnetoplasma mode takes place via single-particle excitations of the electron system by the incident light wave and (2) the magnetoplasma wave is coupled to the single-particle excitations by the vector potential of its electromagnetic field, which in thermal equilibrium is determined by the fluctuation-dissipation theorem for the system under consideration. In the limit where the Raman frequency shift is small compared to the incident frequency, it is possible to make contact with phenomenological theory. For wave vector and dc magnetic field sufficiently small for quantum effects to be neglected, the theory predicts three principal phenomenological scattering mechanisms: free carrier fluctuations, electro-optic effect, and magneto-optic effect.

Operated with support from the U. S. Air Force.