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arXiv · 2604.23109

Effective phonon models based on symmetry-adapted multipole basis -- Hidden chiral phonon angular momentum splitting in ferroaxial systems

Yu Xie·Rikuto Oiwa·Satoru Hayami
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Abstract

We propose a symmetry-based framework for constructing effective harmonic phonon models using a symmetry-adapted multipole basis. By decomposing the force-constant matrix into bond-centered electric multipoles, we identify the minimal microscopic ingredients responsible for phonon angular-momentum splitting. Applying this framework to a minimal zigzag-chain model, we show that ferroaxial order gives rise to a hidden sublattice-resolved chiral phonons, while an additional polar contribution leads to finite global chirality. Our results provide a unified symmetry-based description of hidden and emergent phonon phenomena and suggest a route to control phonon properties via electronic orderings and external fields.

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Yu Xie, Rikuto Oiwa, Satoru Hayami. 2026-04-25. Effective phonon models based on symmetry-adapted multipole basis -- Hidden chiral phonon angular momentum splitting in ferroaxial systems. https://arxiv.org/abs/2604.23109

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