Colossal negative magnetoresistance in a 2D electron gas

TL;DR

This study reports a colossal negative magnetoresistance in a 2D electron gas within GaAs/AlGaAs quantum wells, characterized by a significant resistivity drop at low magnetic fields and a linear temperature dependence, highlighting phonon interactions.

Contribution

It reveals a new type of negative magnetoresistance in 2D electron gases that is not parabolic and persists at high fields and temperatures, emphasizing phonon effects.

Findings

Resistivity drops by over an order of magnitude at ~1 kG magnetic field.

Resistivity's temperature dependence is linear from 1 to 30 K.

The MR effect persists at high in-plane magnetic fields and temperatures.

Abstract

We report on a colossal negative magnetoresistance (MR) in GaAs/AlGaAs quantum well which, at low temperatures, is manifested by a drop of the resistivity by more than an order of magnitude at a magnetic field $B \approx 1$ kG. In contrast to MR effects discussed earlier, the MR reported here is not parabolic, even at small $B$, and persists to much higher in-plane magnetic fields and temperatures. Remarkably, the temperature dependence of the resistivity at $B \approx 1$ kG is linear over the entire temperature range studied (from 1 to 30 K) and appears to coincide with the high-temperature limit of the zero-field resistivity, hinting on the important role of acoustic phonons.