Large thermal Hall effect in MnPS₃

Recent studies have demonstrated that the thermal Hall effect (THE) can originate from magnons (magnon Hall effect), phonons (phonon Hall effect), or their combination (magnon-polaron Hall effect). The magnon-polaron Hall effect, first observed in Fe₂Mo₃O₈, is particularly intriguing as its thermal Hall signal can be remarkably large. In this study, we explore the THE in MnPS₃, an insulating antiferromagnetic material exhibiting a spin-flop (SF) transition and significant magnetoelastic coupling, making it a strong candidate for studying the THE originating from spin-lattice coupling. We report an exceptionally large thermal Hall angle down to 4 K and show that it cannot be accounted for by standard calculations based on the intrinsic magnon-polaron Berry curvature. Our findings provide an in-depth analysis of the role of the SF transition in the thermal properties of MnPS₃and call for further theory development on magnon-phonon coupling and scattering to reveal their influence on transverse heat transport.