Novel chiral quantum spin liquids in Kitaev magnets

TL;DR

This paper predicts a new type of chiral quantum spin liquid in Kitaev magnets under strong magnetic fields, featuring two Majorana edge modes and topological transitions, with potential experimental detection via thermal Hall conductance.

Contribution

It introduces a novel chiral quantum spin liquid phase in Kitaev magnets induced by strong magnetic fields and Dzyaloshinskii-Moriya interactions, expanding the understanding of topological quantum states.

Findings

A topological transition to a gapped quantum spin liquid with two Majorana edge modes occurs under strong magnetic fields.

Dzyaloshinskii-Moriya interaction induces a chiral spin liquid with equal Berry phases at Dirac points.

Thermal Hall conductance can experimentally detect these new topological quantum spin liquids.

Abstract

Mott insulators under sufficiently strong spin-orbit coupling can display quantum spin liquid phases with topological order and fractional excitations. Quantum magnets with pure Kitaev spin exchange interactions can host a gapped quantum spin liquid with a single Majorana edge mode propagating in the counter-clockwise direction when a small positive magnetic field is applied. Here, we show how under a sufficiently strong positive magnetic field a topological transition into a gapped quantum spin liquid with two Majorana edge modes propagating in the clockwise direction occurs. The Dzyaloshinskii-Moriya interaction is found to turn the non-chiral Kitaev's gapless quantum spin liquid into a chiral one with equal Berry phases at the two Dirac points. Thermal Hall conductance experiments can provide evidence of the novel topologically gapped quantum spin liquid states predicted.