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arXiv · 2403.13306

Thermodynamic origin of the phonon Hall effect in a honeycomb antiferromagnet

Qingkai Meng·Xiaokang Li·Jie Liu·Lingxiao Zhao·Chao Dong·Zengwei Zhu·Liang Li·Kamran Behnia
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Abstract

The underlying mechanism of the thermal Hall effect (THE) generated by phonons in a variety of insulators is yet to be identified. Here, we report on a sizeable thermal Hall conductivity in NiPS$_3$, a van der Waals stack of honeycomb layers with a zigzag antiferromagnetic order below $T_N$ = 155 K. The longitudinal ($\kappa_{aa}$) and the transverse ($\kappa_{ab}$) thermal conductivities peak at the same temperature and the thermal Hall angle, at this peak, respects a previously identified bound. The amplitude of $\kappa_{ab}$ is extremely sensitive to the amplitude of magnetization along the $b$-axis, in contrast to the phonon mean free path, which is not at all. We show that the magnon and acoustic phonon bands cross each other along the $b^\ast$ orientation in the momentum space. The relevance of a thermodynamic property, combined with the irrelevance of the mean free path, points to an intrinsic origin.

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Qingkai Meng, Xiaokang Li, Jie Liu, Lingxiao Zhao, Chao Dong, Zengwei Zhu, Liang Li, Kamran Behnia. 2024-03-20. Thermodynamic origin of the phonon Hall effect in a honeycomb antiferromagnet. https://arxiv.org/abs/2403.13306

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