Nonlinear transport in 2D electron gas exhibiting colossal negative magnetoresistance

TL;DR

This study investigates nonlinear transport in a GaAs/AlGaAs quantum well showing colossal negative magnetoresistance, revealing nonmonotonic behavior under bias and confirming classical memory effects theory.

Contribution

It provides experimental evidence of nonlinear transport phenomena in 2D electron gases and supports classical memory effects as an explanation for colossal negative magnetoresistance.

Findings

Resistivity exhibits nonmonotonic dependence on magnetic field under bias.

Resistivity increases linearly with current, with a rate scaling inversely with magnetic field.

Results align with classical memory effects theory for dilute scatterers.

Abstract

We report on nonlinear transport measurements in a GaAs/AlGaAs quantum well exhibiting a colossal negative magnetoresistance effect. Under applied dc bias, the magnetoresistance becomes nonmonotonic, exhibiting distinct extrema that move to higher magnetic fields with increasing current. In the range of magnetic fields corresponding to the resistivity minimum at zero bias, the resistivity increases linearly with current and the rate of this increase scales with the inverse magnetic field. The latter observation is consistent with the theory, proposed more than 35 years ago, considering classical memory effects in the presence of strong, dilute scatterers.