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

Magneto-optical oscillations in the intensity of photoluminescence transiti ons in AlGaAs/InGaAs/GaAs asymmetric quantum wells with two occupied electr onic subbands have been studied. The minima of the oscillations for the fir st excited electronic subband occur at resonant polaron conditions ((h) ove r bar omega(LO) = N (h) over bar omega(c)) in which the emission of LO phon ons is strongly enhanced and are due to an increase of the LO phonon scatte ring 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 betwee n the magneto-optical and the Shubnikov-de Haas oscillations. (C) 1998 Else vier Science B.V. All rights reserved.