Non-linear Transport in a Two-Dimensional Electron Gas in Magnetic Fields

Maxim Vavilov

University of Wisconsin, USA

We present a theoretical description of a nonlinear response of a two-dimensional electron gas to applied electric fields. We discuss the quantum Boltzmann equation for the two-dimensional electron gas at large values of the filling factor. This equation takes into account scattering off disorder with arbitrary dependence on the scattering angle. We show that the non-linearity has two contributions. The first contribution originates from the formation of a non-equilibrium electron distribution function and dominates in relatively weak electric fields. The second contribution describes the geometrical resonance in the inter-Landau-levels transition rates and becomes important in stronger fields. This theoretical model is applied for analysis of recent measurements of the non-linear magnetoresistance in high mobility two-dimensional electron systems. We also discuss the effects of microwave radiation and electron-phonon coupling on the observed magnetoresistance curves.