Electronic raman scattering in quantum wells: Coupled levels in tilted magnetic fields

摘要

We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAs---AlxGa1-xAs quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited electrons and 1s -- 1s' donor excitations. Tilted fields lead to subband-Landau level and 1s' - 2p+ coupling. Experimental results for the latter case agree very well with variational calculations. Data on combined intersubband-cyclotron resonances at arbitrary tilt angles are accurately described by expression valid for wells. The parabolic approach is shown to provide a good approximation in situations where coupling to higher subbands can be neglected.