We investigate the thermal Hall effect in a Kitaev-Heisenberg system, a model for Kitaev candidate α-RuCl3, in the presence of the coupling between spin and phonon arising from chlorine atoms' vibration. We observe that the coupling modifies the relative stability between different magnetic states under a magnetic field, especially stabilizing a canted zigzag antiferromagnetic state. Remarkably, the spin-phonon interaction has distinct effects on the thermal Hall conductivity in different magnetically ordered states. For the canted zigzag state, which is relevant to α-RuCl3, the spin-phonon interaction enhances the energy gap that is induced by a magnetic field and suppresses the thermal Hall conductivity at low temperatures. Importantly, we find that the spin-phonon interaction destabilizes the quantized thermal Hall effect in the spin-liquid state. Our results demonstrate a crucial role of phonon degrees of freedom to the thermal Hall effect in Kitaev materials.
@article{arxiv.2112.06107,
title = {Thermal Hall Effect in the Kitaev-Heisenberg System with Spin-Phonon Coupling},
author = {Shaozhi Li and Satoshi Okamoto},
journal= {arXiv preprint arXiv:2112.06107},
year = {2022}
}