Topological Thermal Hall Effect in Frustrated Kagom\'e Antiferromagnets

TL;DR

This paper predicts a thermal Hall effect in frustrated kagome antiferromagnets driven by scalar spin chirality, expanding understanding of thermal transport phenomena in quantum magnetic materials.

Contribution

It introduces a novel mechanism for thermal Hall effect in frustrated kagome magnets via scalar spin chirality, differing from previous Dzyaloshinsky-Moriya interaction based explanations.

Findings

Thermal Hall effect can be induced by scalar spin chirality in kagome antiferromagnets.

Chiral spin textures under magnetic fields can generate non-coplanar spin configurations.

Potential for observing thermal Hall effect in materials like herbertsmithite and Ca10Cr7O28.

Abstract

In frustrated magnets the Dzyaloshinsky-Moriya interaction arising from spin-orbit coupling can induce a magnetic long-range order. Here, we report a theoretical prediction of thermal Hall effect in frustrated kagom\'e magnets such as KCr$_3$(OH)$_6$(SO4)$_2$ and KFe$_3$(OH)$_{6}$(SO$_{4}$)$_2$. The thermal Hall effects in these materials are induced by scalar spin chirality as opposed to DMI in previous studies. The scalar spin chirality originates from magnetic-field-induced chiral spin configuration due to non-coplanar spin textures, but in general it can be spontaneously developed as a macroscopic order parameter in chiral quantum spin liquids. Therefore, we infer that there is a possibility of thermal Hall effect in frustrated kagom\'e magnets such as herbertsmithite ZnCu$_3$(OH)$_6$Cl$_2$ and the chromium compound Ca$_{10}$Cr$_7$O$_{28}$, although they also show evidence of magnetic order in the presence of a magnetic field or pressure.