# Phonon Thermal Hall Effect in a non-Kramers Paramagnet

## TL;DR

This paper presents a minimal theoretical model for the phonon thermal Hall effect in non-Kramers paramagnets, explaining experimental observations through resonant phonon-pseudospin scattering.

## Contribution

The work introduces a simple model with linear pseudospin-phonon coupling for non-Kramers doublets, providing a theoretical framework for phonon thermal Hall effects.

## Key findings

- Qualitative agreement with experiments in Pr2Ir2O7
- Resonant phonon-pseudospin scattering explains Hall effect
- Model reproduces thermal conductivities observed experimentally

## Abstract

With an increasing number of experiments observing phonon thermal Hall effect in magnets, it is theoretically desired to have a minimal model for the phonon thermal Hall effect. In this work, we study a simple model of acoustic phonons and uncorrelated paramagnetic doublets. When the doublets are non-Kramers, a linear pseudospin-phonon coupling is allowed by time-reversal symmetry and yields resonant phonon-pseudospin scattering. We compute the thermal longitudinal and Hall conductivities of the model and found qualitative agreement with recent experiments in $\rm{Pr}_2\rm{Ir}_2\rm{O}_7$ [Uehara et al.,Nat Commun 13, 4604 (2022)].