On the Origin of Non-Saturating Linear Magnetoresistivity

TL;DR

This paper explains the origin of non-saturating linear magnetoresistivity in 2D conductors, highlighting the roles of nonlocal effects, charge density fluctuations, and misaligned currents, challenging previous assumptions about mobility fluctuations.

Contribution

It introduces a self-consistent model showing how nonlocal mechanisms cause linear magnetoresistivity, emphasizing the importance of charge density fluctuations over mobility fluctuations.

Findings

Linear magnetoresistivity arises from nonlocal effects and charge density fluctuations.

Mobility fluctuations are not the primary cause of linear magnetoresistivity.

Linear magnetoresistivity is common in low-density, strongly magnetized regimes.

Abstract

The observation of non-saturating classical linear magnetoresistivity has been an enigmatic phenomenon in solid state physics. We present a study of a two-dimensional ohmic conductor, including local Hall effect and a self-consistent consideration of the environment. An equivalent-circuit scheme delivers a simple and convincing argument why the magnetoresistivity is linear in strong magnetic field, provided that current and biasing electric field are misaligned by a nonlocal mechanism. A finite-element model of a two-dimensional conductor is suited to display the situations that create such deviating currents. Besides edge effects next to electrodes, charge carrier density fluctuations are efficiently generating this effect. However, mobility fluctuations that have frequently been related to linear magnetoresistivity are barely relevant. Despite its rare observation, linear magnetoresitivity is rather the rule than the exception in a regime of low charge carrier densities, misaligned current pathways and strong magnetic field.