Microwave-Induced Suppression of Dissipative Conductivity and Its Shubnikov–de Haas Oscillations in Two-Dimensional Electron Systems: Effects of Dynamic Electron Localization and Plasma Reflection

Abstract

We present a model for microwave photoconductivity in two-dimensional electron systems (2DESs) in a magnetic field at microwave frequencies lower than the electron cyclotron frequency when the intra-Landau level (LL) transitions dominate. Using this model, we explain the effect of the decrease in the 2DES dissipative conductivity (and resistivity) and smearing of its Shubnikov–de Haas oscillations caused by microwave radiation observed recently. The model invokes the concept of suppression of elastic impurity scattering of electrons by the microwave electric field. We calculated the dependence of the 2DES conductivity associated with intra-LL transitions as a function of the radiation and cyclotron frequencies and microwave power. We take into account the effect of plasma reflection of microwaves from 2DES resulting in a distinction between the ac microwave electric field acting on electrons and that generated by a microwave source. The obtained dependences are consistent with the results of recent experimental observations.