MAGNETOINTERSUBBAND OSCILLATIONS OF CONDUCTIVITY IN A 2-DIMENSIONAL ELECTRON-SYSTEM

Magnetoconductivity of the two-dimensional electron gas occupying two size-quantization subbands is studied theoretically. When the bottoms of subbands are separated by an integer number of Landau levels, the s taircases of Landau levels in both subbands are completely aligned. Fo r such values of magnetic field the intersubband scattering is enhance d. As it was pointed out by Polyanovsky, this results in additional Sh ubnikov-de Haas oscillations of conductivity with magnetic field, with period depending on subband separation, and amplitude depending weakl y on temperature, provided that a large number of Landau levels in eac h subband are occupied. In the calculation of conductivity we make use of the self-consistent Born approximation generalized to the case of two subbands. An analytical theory for the case of strong disorder and numerical results for the case of weak disorder are presented.