Inversion Electrons in InSb in Crossed Electric and Magnetic Fields

Abstract

A crossed field configuration for electrons is created by the strong electric field that is perpendicular to a space-charge layer and a magnetic field that is applied parallel to the layer. On InSb simultaneously diamagnetically shifted intersubband resonances and cyclotron resonances have been observed in inversion layers in this crossed field configuration. These experiments are reviewed and are compared with simple analytical expressions for eigenenergies and optical excitation strengths of the hybrid electric-magnetic surface band structure in the triangular-well approximation of the electrostatic potential (constant surface electric field). In addition to the one-band effective-mass approximation, we also treat a two-band model that takes into account the effects of nonparabolicity in narrow-gap semiconductors. In particular, we find that cyclotron masses of inversion electrons on InSb in crossed fields show in a rather spectacular way the analogy between electrons in narrow-gap semiconductors and relativistic electrons in vacuum and we demonstrate the destruction of the Landau quantization in strong transverse electric fields.