Anomalous Negative Magnetoresistance Caused by Non-Markovian Effects

TL;DR

This paper develops a theoretical explanation for anomalous low-field magnetoresistance in two-dimensional electron systems, highlighting non-Markovian effects that cause a transition from parabolic to linear magnetoresistance with increasing magnetic field.

Contribution

It introduces a theoretical model accounting for non-Markovian effects in electron scattering, explaining the observed anomalous magnetoresistance behavior.

Findings

Magnetoresistance is parabolic and inversely proportional to the gas parameter at low fields.

Magnetoresistance becomes linear with increasing magnetic field.

The theoretical results agree well with experimental data and numerical simulations.

Abstract

A theory of recently discovered anomalous low-field magnetoresistance is developed for the system of two-dimensional electrons scattered by hard disks of radius $a,$ randomly distributed with concentration $n.$ For small magnetic fields the magentoresistance is found to be parabolic and inversely proportional to the gas parameter, $ \delta \rho_{xx}/\rho \sim - (\omega_c \tau)^2 / n a^2.$ With increasing field the magnetoresistance becomes linear $\delta \rho_{xx}/\rho \sim - \omega_c \tau $ in a good agreement with the experiment and numerical simulations.