Altermagnetism, ARPES, symmetry, non-relativistic band splitting

TL;DR

This review discusses how ARPES techniques reveal nonrelativistic band splitting and spin textures in altermagnets, emphasizing symmetry origins and potential for spintronic applications.

Contribution

It systematically reviews the role of ARPES in visualizing altermagnetic spin textures and distinguishes different magnetic orders within the spin-group framework.

Findings

ARPES directly visualizes nonrelativistic band splitting in altermagnets.

Symmetry analysis explains the origin of spin polarization in various magnetic orders.

Multiple candidate materials exhibit characteristic altermagnetic properties.

Abstract

Altermagnetism arises from composite real-space and spin-space symmetries, combining zero net magnetization with pronounced momentum-dependent spin splitting. This review highlights the pivotal role of angle-resolved photoemission spectroscopy (ARPES), along with its spin-resolved (SARPES) and circular-dichroism (CD-ARPES) variants, in directly visualizing nonrelativistic band splitting and spin textures in altermagnets. Within the spin-group framework, we distinguish ferromagnetic, antiferromagnetic, and altermagnetic orders and elucidate the symmetry origin of spin polarization. We then systematically review representative systems: the debated d-wave prototype RuO2, layered d-wave altermagnets KV2Se2O and Rb1-delta V2Te2O, and a series of g-wave compounds including MnTe (domain-tunable) and CrSb (topological), together with the noncoplanar antiferromagnet MnTe2 and other emerging candidate platforms. Overall, ARPES has become a key probe for resolving symmetry-driven spin splitting. Future advances in micro/nano-beam and in-situ spectroscopies, combined with strain and domain engineering, heterostructure design, and exploration of broader unconventional magnetic states, are expected to drive the joint evolution of altermagnetism and photoemission spectroscopy, paving the way for spintronic and correlated quantum research.