RESONANT MAGNETO-RAMAN SCATTERING IN GAAS

Resonant magneto-Raman scattering by LO phonons in GaAs has been measured. Theoretical results of the preceding paper are applied to sort out Raman processes which contribute to the enhancement of the Stokes LO-phonon intensity in incoming and outgoing resonance channels. Conditions for magnetic-field- induced double resonance are investigated and verified by the experiments. The mixing of valence levels gives rise to a novel type of double resonance which only involves heavy- or light-mass holes. The onset of such situation, which for light-mass levels should occur at about 15 T, is observed. The increasing importance of Raman processes involving only heavy-mass levels is found to be the origin of the seemingly paradoxical finding that for laser energies close to the direct edge outgoing resonances dominate, whereas incoming resonances take over in regions of large magnetic fields and laser frequencies well above the E0 fundamental gap. © 1990 The American Physical Society.