RESONANT RAMAN-SCATTERING IN QUANTUM-WELLS IN HIGH MAGNETIC-FIELDS - DEFORMATION-POTENTIAL INTERACTION

A theoretical study of one-phonon resonant Raman scattering in a quantum well (QW) in high magnetic fields has been performed. The Raman profiles are calculated as a function of magnetic field, quantum-well thickness, and laser frequency. The basic theory is first developed assuming parabolic masses in the plane perpendicular to the growth direction of the QW. Selection rules for deformation-potential-allowed scattering are given and a compact analytical expression for the Raman-scattering efficiency is obtained for infinite barriers. The double-resonance conditions are derived as a function of the magnetic field or well thickness. In a second part of the work, the heavy-hole-light-hole valence-band admixture has been taken into account through a 4 x 4 Luttinger Hamiltonian. It is shown that phonons couple the heavy component of a band with the light component of the other via a deformation potential, giving rise to the selection rule DELTA-n = +/- 2 (DELTA-N = 0 for the Landau quantum number). The Raman polarizability has been calculated for a 100-angstrom GaAs/AlAs multiple QW for different magnetic fields as a function of laser energy and magnetic field. Comparison with recent experimental results allows us to classify the leading double resonance as due to transitions between the excitons formed with the first and second heavy-hole subbands, and the first electron subband with Landau quantum number N = 1.