Magneto-optical oscillations in the photoluminescence of quantum wells and the resonant polaron effect

Abstract

Magneto-optical oscillations in the intensity of photoluminescence transitions in AlGaAs/InGaAs/GaAs asymmetric quantum wells with two occupied electronic subbands have been studied. The minima of the oscillations for the first excited electronic subband occur at resonant polaron conditions (ℏωLO=Nℏωc) in which the emission of LO phonons is strongly enhanced and are due to an increase of the LO phonon scattering of electrons near the Fermi level, which is confirmed by the increase verified in the photoluminescence linewidth at resonant polaron conditions. This effect can also explain the small difference in phase observed between the magneto-optical and the Shubnikov–de Haas oscillations.