Landau Level Mixing in Asymmetric Quantum Wells

Abstract

Lowering of the symmetry of electronic states in quantum wells with respect to bulk semiconductors has a profound effect on the selection rules governing the optical transitions between the valence and the conduction subbands. These transitions involve excitonic states of electron-hole pairs and thus provide useful information about the properties of excitons. The situation is particularly interesting when a magnetic field is applied along the growth axis of a quantum well system. The interband magnetoabsorption spectrum is then composed of a series of excitonic lines associated with different Landau levels. The symmetry of those states can be resolved by analysing the absorption or photoluminescence excitation spectra taken at circular polarisation of incident light parallel to the quantum well symmetry axis ($\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\frown}$}}{z}$ axis).