Hole-subband mixing in quantum wells: A magnetooptic study

The effect of mixing of the hole subbands on the magnetooptical interband transitions in quantum wells is investigated in a six-band envelope-function approach. Our results compare favorably with magnetooptical experiments on GaAs quantum wells and help considerably in their understanding. In particular, the explicit evaluation of the transition strengths is necessary in order to explain the experimental findings: The relaxation of the usual selection rules for optical transitions due to the strong mixing between the hole subbands has a remarkable effect on the observed absorption spectra and is well accounted for by our calculation. Excitonic effects due to the electron-hole Coulomb interaction are included in a simplified manner. A higher band-edge electron mass is needed in order to fit the experimental data; we believe that this is an indication that nonparabolicity effects are stronger than usually assumed.