Chiral spin-order in some purported Kitaev spin-liquid compounds

Abstract

We examine recent magnetic torque measurements in two compounds, $\gamma$-Li${}_2$IrO${}_3$ and RuCl${}_3$, which have been discussed as possible realizations of the Kitaev model. The analysis of the reported discontinuity in torque, as an external magnetic field is rotated across the $c-$axis in both crystals, suggests that they have a translationally-invariant chiral spin-order of the from $<{\mathbf{S}}_i.({\mathbf{S}}_j\times {\mathbf{S}}_k)>\ne 0$ in the ground state and persisting over a very wide range of magnetic field and temperature. An extra-ordinary $|B|B^2$ dependence of the torque for small fields, beside the usual $B^2$ part, is predicted due to the chiral spin-order, and found to be consistent with experiments upon further analysis of the data. Other experiments such as inelastic scattering and thermal Hall effect and several questions raised by the discovery of chiral spin-order, including its topological consequences are discussed.

arXiv commentClearer figures of the experimental data provided. Also clearer exposition and comment on related recent work

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Cited by in corpus (15)

• Ferromagnetic Kitaev interaction and the origin of large magnetic anisotropy in $\alpha$-RuCl${}_3$
• Dynamical and thermal magnetic properties of the Kitaev spin liquid candidate $\alpha$-RuCl${}_3$
• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Magnetoelastic coupling and effects of uniaxial strain in $\alpha$-RuCl${}_3$ from first principles
• On the saw-tooth torque in anisotropic $j_{\mathrm{eff}}=1/2$ magnets: Application to $\alpha$-RuCl${}_3$
• Kitaev magnetism through the prism of lithium iridate
• Investigation of the magnetoelastic coupling anisotropy in the Kitaev material $\alpha$-RuCl${}_3$
• Honeycomb rare-earth magnets with anisotropic exchange interactions
• Reentrant incommensurate order and anomalous magnetic torque in the Kitaev magnet $\beta$-${\text{Li}}_2{\text{IrO}}_3$
• Unconventional magnetic field response of the hyperhoneycomb Kitaev magnet $\beta -{\text{Li}}_2{\text{IrO}}_3$
• Hidden spin-orbital order in the Kitaev hyperhoneycomb $\beta$-Li${}_2$IrO${}_3$
• Anisotropic magnetic interactions in a candidate Kitaev spin liquid close to a metal-insulator transition
• Quantum Thermal Hall effect of chiral spinons on a Kagome strip
• Fractional Spin Quantum Hall Effect in Weakly Coupled Spin Chain Arrays
• Spin-phonon coupling and thermal Hall effect in the Kitaev model