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arXiv · 2307.03793

Weak-Coupling Theory of Neutron Scattering as a Probe of Altermagnetism

Thomas A. Maier·Satoshi Okamoto
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Abstract

Inelastic neutron scattering provides a powerful probe of the magnetic excitations of quantum magnets. Altermagnets have recently emerged as a new class of magnets with vanishing net magnetization characteristic of antiferromagnets and with a spin-split electronic structure typical of ferromagnets. Here we introduce a minimal Hubbard model with two-sublattice orthorhombic anisotropy as a framework to study altermagnetism. Using unrestricted Hartree-Fock calculations, we find an altermagnetic state for this model that evolves from a metallic state to an insulating state with increasing Hubbard-$U$ Coulomb repulsion. We then examine the inelastic neutron scattering response in these states using random-phase approximation calculations of the dynamic spin susceptibility $\chi''({\bf q}, \omega)$. We find that the magnetic excitation spectrum depends on its chirality for ${\bf q}$ along certain directions in reciprocal space, an observation that may be used in inelastic neutron scattering experiments as a probe of altermagnetism.

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Thomas A. Maier, Satoshi Okamoto. 2023-07-07. Weak-Coupling Theory of Neutron Scattering as a Probe of Altermagnetism. https://doi.org/10.1103/physrevb.108.l100402

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