Thermodynamic origin of the phonon Hall effect in a honeycomb antiferromagnet

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.

7 pages, 4 figures, Supplemental Materials included

Cited by in corpus (1)

• Phonon thermal Hall as a lattice Aharonov-Bohm effect