Magnetoresistance Oscillations in Two-dimensional Electron Systems Induced by AC and DC Fields

TL;DR

This study investigates how simultaneous AC and DC fields influence magnetoresistance oscillations in high-mobility two-dimensional electron systems, revealing complex interactions and a new resonant condition affecting photoresistance.

Contribution

It introduces the concept of a combined resonant condition to explain electron transitions under simultaneous AC and DC excitations in 2D electron systems.

Findings

DC fields modify microwave photoresistance in complex ways

Photoresistance maxima and minima interchange due to combined effects

Microwave-induced zero resistance can be suppressed by DC fields

Abstract

We report on magnetotransport measurements in a high-mobility two-dimentional electron system subject simultaneously to AC (microwave) and DC (Hall) fields. We find that DC excitation affects microwave photoresistance in a nontrivial way. Photoresistance maxima (minima) evolve into minima (maxima) and back, reflecting strong coupling and interplay of AC- and DC-induced effects. Most of our observations can be explained in terms of indirect electron transitions using a new, ``combined'' resonant condition. Observed quenching of microwave-induced zero resistance by a DC field cannot be unambiguously linked to a domain model, at least until a systematic theory treating both excitation types within a single framework is developed.