Theoretical model for negative giant magnetoresistance in ultra-high-mobility 2D electron systems

TL;DR

This paper presents a theoretical model explaining the negative giant magnetoresistance observed in ultra-high-mobility 2D electron systems at low temperatures, highlighting the role of elastic scattering and Landau level structure.

Contribution

It introduces a transport model tailored for ultraclean 2D electron systems, explaining the negative giant magnetoresistance phenomenon with detailed calculations.

Findings

Scattering rate and magnetoresistance decrease at low magnetic fields.

The effect depends on temperature and in-plane magnetic field.

Landau level width is much smaller than cyclotron energy in the regime studied.

Abstract

We report on theoretical studies of the recently discovered negative giant magnetoresistance in ultraclean two-dimensional electron systems at low temperatures. We adapt a transport model to a ultraclean scenario and calculate the elastic scattering rate (electron-charged impurity) in a regime where the Landau level width is much smaller than the cyclotron energy. We obtain that for low magnetic fields the scattering rate and, as a consequence, the longitudinal magnetoresistance dramatically drop because of the small density of states between Landau levels. We also study the dependence of this striking effect on temperature and an in-plane magnetic field.