Effect of microwave radiation on the nonlinear resistivity of a two-dimensional electron gas at large filling factors

We study transport properties of a two-dimensional electron gas, placed in a classically strong perpendicular magnetic field and in constant and oscillating in-plane electric fields. The analysis is based on a quantum Boltzmann equation derived for a weakly disordered two-dimensional electron gas. We consider disordered potential with both longand short-range correlations. Electron scattering off such disorder is not limited to small change in momentum direction, but occurs on an arbitrary angle, including the backscattering. The nonlinearity of the transport in the considered system is a consequence of two coexisting effects: formation of a nonequilibrium distribution function of electrons and modification of the scattering rate off the disorder in the presence of dc and ac electric fields. This work describes both effects in a unified way. The calculated dissipative component of electric current oscillates as a function of the electric-field strength and frequency of microwave radiation in qualitative agreement with experiments.