Surface cyclotron resonance on InSb in Voigt configuration.

Abstract

Magnetic fields parallel to space-charge layers on semiconductors define a crossed-field configuration with strong electric fields. Analytical expressions for the resulting hybrid electric-magnetic surface band structure and its optical transitions are derived in the triangular-well approximation of the electrostatic potential. The results of the one-band effective-mass approximation are extended to a two-level model that accounts for the nonparabolicity of narrow-band-gap semiconductors such as InSb. In the hybrid surface band structure, electrons with bulklike wave functions exist, allowing the experimental study of conduction-band cyclotron resonance in crossed fields. This is done in a wide range of frequencies, magnetic fields, and inversion electron densities, i.e., electric field strengths. The experimental results are discussed within the proposed models and are compared with experiments on other semiconductors. Specifically, the destruction of the Landau quantization in crossed electric and magnetic fields is investigated, both theoretically and experimentally; polarons are also studied. This is possible because of the absence of coupled plasma cyclotron--LO-phonon modes in the present degenerate electron system.