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arXiv · 2608.10735

Quantum Mechanism of Piezomagnetism in Higher-Spin Altermagnets

Daisuke Yamamoto·Makoto Naka
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Abstract

We investigate piezomagnetism in higher-spin altermagnets with easy-plane single-ion anisotropy using a flavor-wave approach. We show that quantum fluctuations of higher-spin collective modes provide a microscopic origin of the piezomagnetic response. For integer spins, the relevant branch softens and evolves into a Higgs-like amplitude mode on approaching the large-$D$ transition, endowing the excitation with a sizable dipolar component and producing a pronounced enhancement of piezomagnetism. By contrast, in half-integer systems the higher-spin branches are progressively separated from the low-energy dipolar sector as the anisotropy increases, which suppresses their contribution to the response. This integer-half-integer contrast directly links macroscopic piezomagnetism to the low-energy fate of multipolar excitations. Our results establish piezomagnetism as a probe of higher-spin quantum dynamics and identify higher-spin altermagnets as a promising setting for quantum magnetoelastic responses.

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Daisuke Yamamoto, Makoto Naka. 2026-08-11. Quantum Mechanism of Piezomagnetism in Higher-Spin Altermagnets. https://arxiv.org/abs/2608.10735

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