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arXiv · 2604.06785

Magnetic-field switching of exciton-magnon coupling in LiNiPO$_4$

Bei Sun·Zhuo Yang·Julian Shibuya·Koichi Kindo·Kenta Kimura·Atsuhiko Miyata
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Abstract

Exciton-magnon transitions provide a fundamental optical fingerprint of coupled excitonic and magnetic excitations in antiferromagnets. However, controlling such coupled excitations by external fields remains a key challenge. Here we report the temperature and magnetic-field evolution of exciton-magnon coupling in the magnetoelectric antiferromagnet LiNiPO$_4$ using pulsed magnetic fields up to 50 T. The magnon sideband intensity exhibits sharp switching across field-induced magnetic phases, with strong suppression in plateau phases and enhancement in canted spin states. This behavior is attributed to the interplay between the thermal magnon population and the spin-dependent optical transition matrix element. These results demonstrate that magnetic-field control of spin degrees of freedom enables selective switching of exciton-magnon coupling in antiferromagnets.

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Bei Sun, Zhuo Yang, Julian Shibuya, Koichi Kindo, Kenta Kimura, Atsuhiko Miyata. 2026-04-08. Magnetic-field switching of exciton-magnon coupling in LiNiPO$_4$. https://arxiv.org/abs/2604.06785

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