Strong magnetoresistance induced by long-range disorder

TL;DR

This paper investigates how long-range disorder causes significant positive magnetoresistance in two-dimensional fermion systems, highlighting the impact of non-Markovian transport effects in weak, smooth random potentials or magnetic fields.

Contribution

It provides a semiclassical calculation showing the strong positive magnetoresistance induced by long-range disorder, especially in random magnetic fields, expanding understanding of disorder effects on transport.

Findings

Strong positive magnetoresistance observed in broad magnetic field range

Magnetoresistance significantly larger in random magnetic fields than at zero field

Non-Markovian transport effects are key to the observed phenomena

Abstract

We calculate the semiclassical magnetoresistivity $\rho_{xx}(B)$ of non-interacting fermions in two dimensions moving in a weak and smoothly varying random potential or random magnetic field. We demonstrate that in a broad range of magnetic fields the non-Markovian character of the transport leads to a strong positive magnetoresistance. The effect is especially pronounced in the case of a random magnetic field where $\rho_{xx}(B)$ becomes parametrically much larger than its B=0 value.