Robust d-wave altermagnetism in XCr₂Y₂O （X=K, Rb, Cs; Y=S, Se, Te） family

Abstract

The KV₂Se₂O, Rb_1-δV₂Te₂O and Cs_1-δV₂Te₂O are experimentally confirmed to adopt either C-type or G-type antiferromagnetic configuration, corresponding to apparent or hidden altermag-netism. However, their nearly degenerate energies lead to inconsistent experimental assignments between the two antiferromagnetic configurations. Here, we predict that the experimentally syn-thesized RbCr₂Se₂O is a robust d-wave altermagnetic metal, since the energy difference between C-type and G-type configurations is large, which is independent of electron correlation strength and van der Waals interaction. Upon applying in-plane uniaxial strain, RbCr₂Se₂O can generate a net total magnetic moment via a direct piezomagnetic effect, which is distinct from semiconductor that typically requires carrier doping in addition to strain. This provides an experimental strategy for distinguishing the G-type antiferromagnetic configuration, in which the total magnetic moment remains zero under uniaxial strain. Our work presents an isostructural d-wave altermagnetic RbCr₂Se₂O analogous to KV₂Se₂O, Rb_1-δV₂Te₂O and Cs_1-δV₂Te₂O, which can facilitate further experimental verification. Furthermore, these results are universal across materials of this family XCr₂Y₂O （X=K, Rb, Cs; Y=S, Se, Te）, thus expanding the family of altermagnets.

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Higher Education Press 2026

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