RESONANCE RAMAN-SCATTERING BY INTERFACE PHONONS IN THE MAGNETIC-FIELD IN GAAS/ALAS SUPERLATTICES

The dependence of the intensity of resonant Raman scattering by interface (IF) phonons in GaAs/AlAs superlattices on magnetic field, temperature, and pumping power have been investigated. IF phonon spectra, forbidden according to the momentum conservation condition, were observed in a magnetic field. Oscillations of the IF phonon intensity vs. magnetic field, corresponding to the resonance of the exciting light energy with the levels of magneto-excitons which are the intermediate states in the scattering process, have been observed. The IF phonon intensity decreases with increasing temperature. We consider such behaviour to be connected with the temperature-induced delocalization of magneto-excitons bound near static defects which are responsible for the relaxation of the momentum conservation condition. The delocalization energy is observed to increase with magnetic field.