Differential Magnetoresistance Oscillations induced by Microwave and DC Electric Fields

We study magnetoresistance oscillations in two-dimensional electron systems induced by AC and DC fields. We find the position of the maxima and minima in the differential magnetoresistance, $r(\epsilon^{ac},\epsilon^{dc})$ and evaluate the amplitude of magneto-oscillations in terms of various microscopic parameters of the system. We compare our findings with the results of recent experiments by W. Zhang, Phys. Rev. Lett. 98, 106804 (2007).