Linear Magnetoresistance as a Probe of the Neel Vector in Altermagnets with Vanishing Anomalous Hall Effect

TL;DR

This paper proposes linear magnetoresistance as a reliable transport signature for detecting altermagnetism and Neel order in materials where the anomalous Hall effect is absent, aiding experimental identification.

Contribution

It introduces linear magnetoresistance as a novel probe for altermagnets, validated through theory and first-principles calculations, even when the anomalous Hall effect vanishes.

Findings

Linear magnetoresistance exhibits butterfly-like hysteresis near zero field.

This effect is universal across altermagnets according to symmetry analysis.

First-principles calculations confirm the presence of this magnetoresistance in CrSb.

Abstract

Despite time-reversal breaking in momentum space, several altermagnets remain electrically silent to the primary characterization tool anomalous Hall effect, due to crystalline symmetries, jeopardizing their experimental identification. Here, we show that time-reversal odd magnetoresistance exhibiting butterfly-like hysteresis with linear magnetic field dependence near the zero field provides a robust transport signature of altermagnetism even when the anomalous Hall effect vanishes. Using semiclassical theory and symmetry analysis, we demonstrate that this effect is generic across altermagnets and validate it through first-principles calculations in CrSb. Our results establish linear magnetoresistance as an alternative detection of the Berry curvature and Neel order in unconventional antiferromagnets.