Absolute Negative Conductivity in Two-Dimensional Electron Systems Associated with Acoustic Scattering Stimulated by Microwave Radiation

TL;DR

This paper explores the possibility of absolute negative conductivity in 2D electron systems caused by microwave-stimulated acoustic phonon scattering, potentially explaining zero-resistance states observed experimentally.

Contribution

It introduces a new mechanism for ANC involving acoustic phonon scattering stimulated by microwave radiation in 2DES, linking it to experimental zero-resistance phenomena.

Findings

Negative dc conductivity can occur when microwave frequency exceeds electron cyclotron frequency.

The proposed mechanism explains the zero-resistance states observed in experiments.

ANC arises from electron scattering on acoustic phonons with microwave photon absorption.

Abstract

We discuss the feasibility of absolute negative conductivity (ANC) in two-dimensional electron systems (2DES) stimulated by microwave radiation in transverse magnetic field. The mechanism of ANC under consideration is associated with the electron scattering on acoustic piezoelectric phonons accompanied by the absorption of microwave photons. It is demonstrated that the dissipative components of the 2DES dc conductivity can be negative ($\sigma_{xx} = \sigma_{yy} < 0$) when the microwave frequency $\Omega$ is somewhat higher than the electron cyclotron frequency $\Omega_c$ or its harmonics. The concept of ANC associated with such a scattering mechanism can be invoked to explain the nature of the occurrence of zero-resistance ``dissipationless'' states observed in recent experiments.