Effect of dc excitation on microwave-induced resistance oscillations and zero-resistance states in a two-dimensional electron system

We study the effect of dc current on microwave photoresistance in a high-mobility two-dimensional electron system. We find that dc current leads to the evolution of the microwave photoresistance maxima into minima and vice versa. Observed quenching of microwave-induced zero resistance states by a dc current is consistent with the domain model but cannot be unambiguously linked to it. We derive a modified resonant condition for photoresistance oscillations under dc current and suggest interpretation in terms of indirect cyclotron resonances in Hall field tilted Landau levels. Detailed understanding of the evolution requires a systematic theory treating both excitation types within a single framework. (C) 2007 Elsevier B.V. All rights reserved.