PHONON-CYCLOTRON BROADENING OF STOKES SCATTERING FROM POLAR SEMICONDUCTORS

This is an investigation of the effects of electron-phonon coupling in polar semiconductors on the double-cyclotron Stokes scattering. The actual calculation is preceded by a representation of some general aspects of radiation scattering from the point of view of nonlinear susceptibilities. At the lowest temperatures and weak carrier concentrations, it is shown that for the Stokes line shift ω-ω′<(long-wavelongitudinallatticeoptic- modefrequencyω0), a narrow line is expected, displaced below the double-cyclotron frequency 2ωc by a frequency shift or order αω0, where α is the Fröhlich polaron coupling constant. In the immediate vicinity of ω-ω0=ω0, a large discontinuous broadening is expected, which, with further field increase, falls off approximately as (2ωc-ω0)-12. The center of this line is displaced above 2ωc by an amount of order αω0. © 1969 The American Physical Society.