Self-interaction-corrected density-functional theory of subband renormalization in semiconductor quantum wells

Band-gap renormalization effects in optically excited and doped semiconductor quantum wells are evaluated using self-interaction-corrected density-functional theory. Unlike the usual local-density approximation, the self-interaction-corrected theory accounts for the strong subband dependence of the gap renormalization seen in experiments. In our approximate treatment this is due to two-dimensional localization of the wave functions of carriers in the lowest subband. The method is simpler to apply than conventional many-body theories and is found to give results comparable with those obtained in the random-phase approximation.