Band splitting in the altermagnet CrSb

Vladimir P. Mineev

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arXiv · 2602.15131

Band splitting in the altermagnet CrSb

Vladimir P. Mineev

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Abstract

Altermagnets are a class of metallic magnets characterized by spin-split electron bands. Like antiferromagnets they lack spontaneous bulk magnetisation. The initial description of the momentum dependent spin splitting of electron bands in altermagnets was based on the spin groups approach, which is valid when relativistic interactions are neglected. Then the spin-orbit coupling has been taken into account according with time-reversal-odd, even-parity irreducible representations of centrosymmetric point groups considered by R.M.Fernandes et al, Phys.Rev.B {\bf 109}, 024404 (2024). Here we show inadequacy of this formal approach. The problem of electron band splitting should be discussed based on crystal symmetry of concrete altermagnet material. The band spin-splitting in hexagonal altermagnet CrSb is established using magnetic groups formalism that allows to find the additional spin splitting missed in frame of exchange approximation. Another type of spin splitting takes place in so called hidden altermagnets. This type materials do not possess symmetry in respect of space and time inversion but are symmetric in respect of the product of these operations known as toroid symmetry. There is demonstrated the real space spin splitting in materials with toroid symmetry.

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Vladimir P. Mineev. 2026-02-16. Band splitting in the altermagnet CrSb. https://arxiv.org/abs/2602.15131

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