RESONANT ONE-ACOUSTIC-PHONON RAMAN-SCATTERING IN MULTIPLE QUANTUM-WELLS

Raman spectra of GaAs/AlxGa1-xAs MQW's were studied with high magnetic field applied along the growth axis. For photon energies resonant with the e1 - hh1 and e2 - hh2 intersubband transitions we observe a qualitatively different frequency-dependence of the intensity of the folded LA lines, as well as for the broad secondary emission background. Using a simple macroscopic model for the electron-phonon interaction, we demonstrate that this is due to the different symmetries of the well subbands involved in the scattering.