Electronic structure and optical transitions in GaAs-Ga1-xAlxAs(001) superlattices

The authors show that the pseudopotential method can provide an accurate description of the electronic structure and optical properties of semiconductor superlattices. In particular, they compare their results for GaAs-Ga 1-x Al x As(001) superlattices with recent photoconductivity and photoluminescence data and find an excellent agreement between theory and experiment. They show that, even for superlattices with small well width (50-75 AA), a giant mixing between light- and heavy-hole states may occur at the centre of the superlattice Brillouin zone. They discuss the implications of this effect for optical spectra. They also show that optical transitions between states lying above the confining barriers (resonances) in the valence and condition bands have oscillator strengths that are comparable with those corresponding to transitions between bound states.