Bloch-Gr\"uneisen nonlinearity of electron transport in GaAs/AlGaAs heterostructures

TL;DR

This study investigates how direct current induces nonlinear transport in GaAs/AlGaAs heterostructures, revealing a temperature-dependent crossover from Bloch-Gr"uneisen to quasielastic scattering regimes explained by electron-phonon interactions.

Contribution

The paper provides experimental evidence and theoretical analysis of nonlinear electron transport related to Bloch-Gr"uneisen physics in 2D heterostructures.

Findings

Positive differential resistivity correction under direct current

Maximum followed by plateau in resistivity at low temperatures

Nonlinearity diminishes and disappears as temperature increases

Abstract

We report on nonlinear transport measurements in a two-dimensional electron gas hosted in GaAs/AlGaAs heterostructures. Upon application of direct current, the low-temperature differential resistivity acquires a positive correction, which exhibits a pronounced maximum followed by a plateau. With increasing temperature, the nonlinearity diminishes and disappears. These observations can be understood in terms of a crossover from the Bloch-Gr\"uneisen regime to the quasielastic scattering regime as the electrons are heated by direct current. Calculations considering the interaction of electrons with acoustic phonons provide a reasonable description of our experimental findings.