Abstract:
The energy spectrum of an electron in the periodic electrostatic field of a surface superlattice and in a sufficiently strong perpendicular uniform magnetic field consist of narrow minibands formed near Landau levels. The electron Hamiltonian commutes with the magnetic translation operator, and the magnetic field is assumed to be such that the elementary cell of the superlattice is permeated by a magnetic flux equal to a rational number of its quanta. According to Kramers' theorem, in an external magnetic field, the electron dispersion laws are not even functions of quasimomentum projections if the periodic potential of the superlattice field does not have an inversion center $V(\mathrm r)\ne V(\mathrm{-r})$. Therefore, when carriers transition under the action of an electromagnet wave of a certain polarization from occupied magnetic subband to an free one, a non-zero surface electric current occurs in the system. The paper presents model calculations of the density of such a surface current for typical and experimentally realized parameters of superlattices. Depending on the parameters determining the degree of violation of the spatial inversion symmetry of the superlattice, the vector of the surface electron current density can change direction.
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