Angular dependence of magnetophonon resonances in semiconductor superlattices in tilted magnetic fields

摘要

We obtain the angular dependence of magnetophonon resonance (MPR) peaks from longitudinal magnetoconductivities of GaAs/ AlAs semiconductor superlattices for longitudinal optical (LO) phonons in tilted magnetic field applied to the superlattice axis. The MPR peaks of both GaAs and AlAs LO phonon modes using the second derivative of the magnetoconductivities including a miniband width and a periodicity of the potential are shown. As the tilt angle of the applied magnetic fields is increased, the MPR peak positions are shifting to higher magnetic strength region whereas the peak amplitudes are decreasing to vanish at the same condition with experiments. Our results are in qualitative good agreement with the experimental results. We also get the resonance fields for the MPR peak numbers of the GaAs and AlAs LO phonon modes as a function of the tilt angles. Furthermore, we obtain the dispersion relations and the density of states (DOS) including a miniband width, a periodicity of the potential and tilt angles of the tilted magnetic fields to explain the appearance of plateau region between neighboring peak amplitudes. The plateau region can be explained by phenomena such as the shifts, the decreases, and the disappearances of the peak amplitudes of the magnetoconductivities and the second derivative of magnetoconductivities of GaAs/AlAs semiconductor superlattices for tilt angles of the applied magnetic fields. (c) 2006 Elsevier B.V. All rights reserved.