Linear k term valence subband mixing and its effect on electroabsorption of tensile-strained GaAs/AlGaAs quantum wells

We have examined the contribution of a linear k term in the Luttinger Hamiltonian to electroabsorption of strained quantum wells. We have solved the 4×4 effective mass equation for the two lowest valence subbands and an appropriate set of differential equations for excitons. For bound excitons, our results indicate that the hh1→c1 transition is not forbidden for z-polarized electromagnetic waves, that the absorption spectrum can be independent of polarization, and that the hh1 and lh1 absorption edges, contrary to recent suggestion, cannot merge