Nonlinear resistivity of a two-dimensional electron gas in a magnetic field

We develop a theory of nonlinear response to an electric field of a two-dimensional electron gas (2DEG) placed in a classically strong magnetic field. The latter leads to a nonlinear current-voltage characteristic at a relatively weak electric field. The origin of the nonlinearity is twofold: the formation of a nonequilibrium electron distribution function and the geometrical resonance in the inter-Landau-level transitions rates. We find the dependence of the current-voltage characteristics on the electron relaxation rates in the 2DEG.