Far-infrared-induced magnetoresistance oscillations in GaAs Alx Ga1-x As -based two-dimensional electron systems

We report on photoresistance and magnetotransport measurements in a moderate mobility two-dimensional electron system subject to far-infrared (terahertz) radiation. The photoresistance shows radiation induced 1 B -periodic oscillations, which we identify as the terahertz analog of microwave-induced resistance oscillations (MIROs). The MIRO-analog oscillations show a sign reversal in the low-field, high current regime. We simultaneously observe magnetoplasmons and MIRO-analog oscillations with no apparent coupling between them. Using a meandering Hall-bar geometry allows us to greatly enhance sensitivity and detect these oscillations even at elevated temperatures and moderate mobilities.