Crossover between distinct mechanisms of microwave photoresistance in bilayer systems

TL;DR

This study investigates how microwave-induced resistance oscillations in bilayer quantum wells change with temperature, revealing a crossover from an inelastic mechanism to another unidentified mechanism around 4 K.

Contribution

It identifies a temperature-dependent crossover in microwave photoresistance mechanisms in bilayer systems, challenging existing theoretical models.

Findings

Resistance oscillations follow the inelastic mechanism up to ~4 K.

Deviation from the inelastic model occurs at higher temperatures.

A new or modified mechanism likely contributes at elevated temperatures.

Abstract

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.