COUPLED LO PHONON-PLASMON MODES IN A MAGNETIZED SEMICONDUCTOR

The longitudinal optic (LO) phonon susceptibility is evaluated for a semiconductor subjected to a steady magnetic field. Coupling of the lattice vibrations and free electrons is described by a Frohlich interaction, and electron correlation effects are treated within the random phase approximation (RPA). The susceptibility displays resonances, as a function of frequency for a fixed wavevector perpendicular to the applied field, at frequencies that correspond to excitation of coupled LO phonon-plasmon-cyclotron modes. The spectrum and corresponding spectral weights for inelastic neutron scattering are evaluated for a model of n-type GaAs. © 1979 Taylor & Francis Ltd.