Coexistence of Anomalous Hall Effect and Weak Net Magnetization in Collinear Antiferromagnet MnTe

TL;DR

This paper reveals that bulk MnTe, a collinear antiferromagnet, exhibits a detectable magnetic moment and anomalous Hall effect, challenging the assumption of perfect compensation and providing insights into microscopic mechanisms and Berry curvature differences.

Contribution

It demonstrates the coexistence of AHE and weak net magnetization in MnTe and introduces a phenomenological model explaining this phenomenon.

Findings

MnTe shows a small magnetic moment linked to AHE.

A phenomenological model explains the imbalance in Ne9el vector states.

Differences in Berry curvature are highlighted between compensated and uncompensated systems.

Abstract

Anomalous Hall effect (AHE) plays important role in the rapidly developing field of antiferromagnetic spintronics. It has been recently discussed that it can be a feature of not only uncompensated magnetic systems but also in altermagnetic materials. Hexagonal MnTe belongs to this appealing group of compounds exhibiting AHE and is commonly perceived as magnetically compensated. Here, we demonstrate that bulk form of MnTe exhibits small but detectable magnetic moment correlating with hysteretic behaviour of the AHE. We formulate a phenomenological model which explains how this feature allows to create a disbalance between states with opposite N\'eel vector and prevent the AHE signal from averaging out to zero. Moreover, we show how the dependence of AHE on the N\'eel vector arises on microscopical level and highlight the differences in Berry curvature between magnetically compensated and uncompensated systems.