What happens to an altermagnet when you heat it up? Modelling thermal spin fluctuations in CrSb and MnTe
Date:
Contributed talk at the 2026 IOP CMQM Conference.
Abstract
So called ‘altermagnets’ are an intriguing class of magnetically ordered material in which there is a net zero magnetisation, but in which electronic bands are not spin-degenerate on account of the intrinsic symmetries of the underlying crystal structure. In the zero-temperature limit, the magnetic moments (or ‘spins’) will arranged in a perfectly ordered, collinear structure. However, at any finite temperature, thermal noise will cause the spins to deviate from this pristine arrangement. Above some critical temperature (the Néel temperature), long-range magnetic order disappears, and the material transitions to a paramagnetic state. Here, we will present results of ab initio electronic structure calculations performed on two prototypical altermagnets: CrSb, which is metallic; and MnTe, which is semiconducting. We demonstrate that the magnetic phase transition in both materials is well-described by disordered local moment (DLM) theory [1-3] and describe in detail how site-diagonal spin disorder induces changes to calculated band structures. We provide estimates for the Néel temperature of both materials and discuss implications for temperature-dependent transport properties.
References
[1] B. L. Győrffy et al., J. Phys. F: Met. Phys. 15, 1337 (1985). [2] J. Staunton et al., J. Phys. F: Met. Phys. 15, 1387 (1985). [3] I. D. Hughes et al., New J. Phys. 10, 063010 (2008).