Theory of the fractional microwave-induced resistance oscillations

I. A. Dmitriev, A. D. Mirlin, D. G. Polyakov

Published 2007-07-06, updated 2007-11-27Version 2

We develop a systematic theory of microwave-induced oscillations in magnetoresistivity of a 2D electron gas in the vicinity of fractional harmonics of the cyclotron resonance, observed in recent experiments. We show that in the limit of well-separated Landau levels the effect is dominated by a change of the distribution function induced by multiphoton processes. At moderate magnetic field, a single-photon mechanism originating from the microwave-induced sidebands in the density of states of disorder-broadened Landau levels becomes important.