On the magnetoresistance anisotropy of a 2-dimensional electron gas with large half-integer filling factors

TL;DR

This paper investigates how asymmetries in a 2D electron gas influence magnetoresistance anisotropy at large half-integer Landau level fillings, highlighting the role of symmetry breaking in observed transport phenomena.

Contribution

It proposes that symmetry breaking due to asymmetric confinement affects magnetoresistance anisotropy in 2DEGs at specific filling factors.

Findings

Symmetry breaking influences in-plane transport properties.

Asymmetries contribute to magnetoresistance anisotropy.

Structural perfection does not guarantee symmetry invariance.

Abstract

The unsymmetric confinement of the electrons in a typical 2-dimensional electron gas (2DEG) breaks the full cubic symmetry of the in-plane transport properties. A rigorous invariance of the transport under rotation by pi/2 about the cubic axis perpendicular to the plane of the gas no longer holds, even for structurally perfect samples, and asymmetries under rotation by pi/2 are allowed. It is proposed that this symmetry breaking plays a role in the recent observation, by Little et al., of the pronounced anisotropy of the magnetoresistance of a 2DEG at very low temperatures, at large half-integer filling factors of the Landau levels in such a system.