Microwave-induced magnetoresistance of two-dimensional electrons interacting with acoustic phonons

The influence of electron-phonon interaction on magnetotransport in two-dimensional electron systems under microwave irradiation is studied theoretically. Apart from the phonon-induced resistance oscillations which exist in the absence of microwaves, the magnetoresistance of irradiated samples contains oscillating contributions due to electron scattering on both impurities and acoustic phonons. The contributions due to electron-phonon scattering are described as a result of the interference of phonon-induced and microwave-induced resistance oscillations. In addition, microwave heating of electrons leads to a special kind of phonon-induced oscillations. The relative strength of different contributions and their dependence on parameters are discussed. The interplay of numerous oscillating contributions suggests a peculiar magnetoresistance picture in high-mobility layers at the temperatures when electron-phonon scattering becomes important.Comment: 12 pages, 2 figure

Crossover between distinct mechanisms of microwave photoresistance in bilayer systems

We report on temperature-dependent magnetoresistance measurements in balanced double quantum wells exposed to microwave irradiation for various frequencies. We have found that the resistance oscillations are described by the microwave-induced modification of electron distribution function limited by inelastic scattering (inelastic mechanism), up to a temperature of T*~4 K. With increasing temperature, a strong deviation of the oscillation amplitudes from the behavior predicted by this mechanism is observed, presumably indicating a crossover to another mechanism of microwave photoresistance, with similar frequency dependence. Our analysis shows that this deviation cannot be fully understood in terms of contribution from the mechanisms discussed in theory.Comment: 7 pages, 4 figure

Nonlinear transport and oscillating magnetoresistance in double quantum wells

We study the evolution of low-temperature magnetoresistance in double quantum wells in the region below 1 Tesla as the applied current density increases. A flip of the magneto-intersubband oscillation peaks, which occurs as a result of the current-induced inversion of the quantum component of resistivity, is observed. We also see splitting of these peaks as another manifestation of nonlinear behavior, specific for the two-subband electron systems. The experimental results are quantitatively explained by the theory based on the kinetic equation for the isotropic non-equilibrium part of electron distribution function. The inelastic scattering time is determined from the dependence of the inversion magnetic field on the current.Comment: 20 pages, 10 figure