Suppression of Thermal Conductivity via Singlet-Dominated Scattering in TmFeO$_3$

TL;DR

This study reveals that TmFeO$_3$ exhibits unusually low thermal conductivity due to resonant phonon scattering by Tm$^{3+}$ singlet crystal field levels, impacting quantum magnet thermal transport understanding.

Contribution

It demonstrates that singlet crystal field levels in TmFeO$_3$ cause significant phonon scattering, leading to suppressed thermal conductivity, a novel insight into magnetic and thermal interactions.

Findings

TmFeO$_3$ shows strong thermal conductivity suppression.

Resonant scattering between phonons and Tm$^{3+}$ levels explains this suppression.

Results impact the understanding of thermal transport in quantum magnets.

Abstract

We measured the thermal conductivity of the rare-earth orthoferrites, $R$FeO$_3$, where $R$ = Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb from 3 K to 300 K and see an anomalous strong suppression for TmFeO$_3$ over most of the temperature range. Using a Debye thermal transport model, we demonstrate that this suppression is due to resonant scattering between phonons and the Tm$^{3+}$ $4f$ singlet crystal field levels. The implications of these results are discussed in context of thermal conductivity studies in quantum magnets.