Light Scattering by Electronic Excitations in n-Type GaAs-Al_xGa_1−xAs Superlattices

Abstract

We present a theory of resonant inelastic light scattering by spin-density and charge-density excitations in modulation doped n-type GaAs-Al_xGa_1−xAs superlattices. The scattering cross section is expressed by dynamical polarizability functions, which are calculated by taking into account the Coulomb interaction between carriers, the dynamical exchange-correlation effect, and the interaction with the LO phonons based on the subband structures calculated self-consistently. The spectra calculated in the multiple-quantum-well model are in excellent accord with experimental results so far obtained for low-energy excitations. There remains some disagreement for spectra corresponding to transitions to high-energy excited states.