# Thermal Hall signatures of non-Kitaev spin liquids in honeycomb Kitaev materials

## TL;DR

This paper theoretically investigates the thermal Hall effect in honeycomb Kitaev materials, revealing that certain spin liquids with Dzyaloshinskii-Moriya interactions exhibit a non-quantized thermal Hall conductance under magnetic fields.

## Contribution

It introduces a model explaining the finite thermal Hall effect in gapless U(1) spin liquids with spinon Fermi surfaces influenced by Dzyaloshinskii-Moriya interactions.

## Key findings

- Finite, non-quantized thermal Hall conductance arises due to Dzyaloshinskii-Moriya interactions.
- Internal U(1) gauge flux twists spinon motion, leading to thermal Hall effect.
- The effect is a generic response in Kitaev models across various couplings.

## Abstract

Motivated by the recent surge of field-driven phenomena discussed for Kitaev materials, in particular the experimental observation of a finite thermal Hall effect and theoretical proposals for the emergence of additional spin liquid phases beyond the conventional Kitaev spin liquid, we develop a theoretical understanding of the thermal Hall effect in honeycomb Kitaev materials in magnetic fields. Our focus is on gapless U(1) spin liquids with a spinon Fermi surface, which have been shown to arise as field-induced phases. We demonstrate that in the presence of symmetry-allowed, second-neighbor Dzyaloshinskii-Moriya interactions these spin liquids give rise to a finite, non-quantized, thermal Hall conductance in a magnetic field. The microscopic origin of this thermal Hall effect can be traced back to an interplay of Dzyaloshinskii-Moriya interaction and Zeeman coupling, which generates an internal U(1) gauge flux that twists the motion of the emergent spinons. We argue that such a non-quantized thermal Hall effect is a generic response in Kitaev models for a range of couplings.