Thermal Mechanism of Absolute Negative Conductivity in Two-Dimensional Electron Systems

TL;DR

This paper investigates how microwave-induced electron heating in a 2D electron system can lead to negative dissipative dc conductivity when the electron temperature significantly exceeds the lattice temperature.

Contribution

It provides a theoretical calculation showing the conditions under which negative conductivity occurs due to electron heating in magnetic fields.

Findings

Negative dc conductivity can occur at high electron temperatures

Electron heating by microwave radiation can induce negative conductivity

The model explains experimental observations of zero-resistance states

Abstract

We calculate the dissipative dc conductivity of a two-dimensional electron system in a magnetic field for the situation when its effective temperature exceeds the temperature of the acoustic phonon system. We demonstrate that at sufficiently large difference between the electron and lattice temperatures (sufficiently strong microwave radiation) the dissipative dc conductivity can become negative. As an illustration, the case of the electron heating by microwave radiation is considered.