Description of two-dimensional altermagnetism: Categorization using spin group theory

TL;DR

This paper develops a comprehensive theoretical framework using spin group theory to categorize two-dimensional altermagnetism, identifying new materials and analyzing their spin-momentum locking properties.

Contribution

It introduces seven new spin layer groups for describing 2D altermagnetism and classifies existing materials while predicting new candidates.

Findings

Seven distinct spin layer groups established

Identification of new 2D altermagnetic materials

Analysis of spin-momentum locking properties

Abstract

Altermagnetism, recently spotlighted in condensed matter physics, presents captivating physical properties and holds promise for spintronics applications. This study delves into the theoretical description and categorization of two-dimensional altermagnetism using spin group theory. Employing spin-group formalism, we establish seven distinct spin layer groups, extending beyond the conventional five spin Laue groups, to describe two-dimensional altermagnetism. Utilizing these findings, we classify previously reported two-dimensional altermagnets and identify novel materials exhibiting altermagnetism. Specifically, monolayer MnTeMoO$_6$ and VP$_2$H$_8$(NO$_4$)$_2$ are predicted to be two-dimensional altermagnets. Furthermore, we scrutinize their spin-momentum locking characteristics through symmetry analysis and density functional theory calculations, substantiating their altermagnetic properties.