Line-shape theory of magnetoabsorption in semiconductor superlattices

A line-shape theory for photoabsorption spectra in GaAs-${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As superlattices under the magnetic field is presented. Both the excitonic effect and valence-band mixing are properly taken into account. The theoretical method is valid for any field strength. Both the coupled-well and uncoupled-well regimes are considered. In the coupled-well case, the dispersion along the growth direction gives rise to additional structures in the absorption spectrum compared with that for uncoupled–quantum-well structures. The theoretical predictions for the line shapes of magnetoabsorption spectra of superlattices are in good agreement with the available experimental data.