Radiation-Induced Magnetoresistance Oscillations in a 2D Electron Gas

TL;DR

This paper investigates how microwave radiation causes oscillations in the magnetoresistance of a 2D electron gas, explaining the phenomena through a diagrammatic calculation and predicting new effects at high radiation intensities.

Contribution

The study provides a theoretical framework for radiation-induced magnetoresistance oscillations, matching experimental observations and predicting multi-photon effects at high intensities.

Findings

Oscillations have the correct period and phase

Oscillations increase with radiation intensity

Predicted multi-photon features at high intensity

Abstract

Recent measurements of a 2D electron gas subjected to microwave radiation reveal a magnetoresistance with an oscillatory dependence on the ratio of radiation frequency to cyclotron frequency. We perform a diagrammatic calculation and find radiation-induced resistivity oscillations with the correct period and phase. Results are explained via a simple picture of current induced by photo-excited disorder-scattered electrons. The oscillations increase with radiation intensity, easily exceeding the dark resistivity and resulting in negative-resistivity minima. At high intensity, we identify additional features, likely due to multi-photon processes, which have yet to be observed experimentally.