Resonant Light Scattering and Luminescence in Exciton-Phonon System. I

Abstract

The resonant light scattering of exciton is studied, with particular attention to the coexistence of cascade LO phonon scattering lines, LA phonon scattering structures and luminescence, by using a model system consisting of one exciton band and LO and LA phonons. Including all the higher order exciton-phonon interactions within the ladder approximation combined with the real process approximation, an integral equation for exciton population is derived and solved numerically to give the spectral shape of the emitted light at low temperatures. It is shown how the real and virtual intermediate states contribute to the cascade LO phonon scattering spectrum, and how the broad luminescence band is formed through the accumulation of multiple scatterings of exciton by LA phonons. The effect of the nonradiative decay of exciton on the relative intensity between the Raman and luminescence spectra is also studied.