Microwave Photoresistance in an Ultrahigh Quality GaAs Quantum Well

TL;DR

This study investigates microwave-induced resistance oscillations in an ultrahigh mobility GaAs quantum well, revealing unexpected temperature independence of quantum lifetime and a stronger than predicted temperature dependence of inelastic lifetime.

Contribution

It provides experimental evidence that challenges existing theories by showing temperature-independent quantum lifetime and a stronger temperature dependence of inelastic lifetime in ultrahigh mobility 2D electron gases.

Findings

Quantum lifetime remains temperature-independent from 0.3 K to 1.8 K.

Inelastic lifetime exhibits a stronger temperature dependence than predicted.

Results contradict current theoretical models of electron-electron scattering effects.

Abstract

The temperature dependence of microwave-induced resistance oscillations (MIRO), according to the theory, originates from electron-electron scattering. This scattering affects both the quantum lifetime, or the density of states, and the inelastic lifetime, which governs the relaxation of the nonequilibrium distribution function. Here, we report on MIRO in an ultrahigh mobility ($\mu > 3 \times 10^7$ cm$^2$/Vs) 2D electron gas at $T$ between $0.3$ K and $1.8$ K. In contrast to theoretical predictions, the quantum lifetime is found to be $T$-independent in the whole temperature range studied. At the same time, the $T$-dependence of the inelastic lifetime is much \emph{stronger} than can be expected from electron-electron interactions.