Angle-dependent thermodynamics of $\alpha$-RuCl${}_3$

Abstract

Thermodynamics of the Kitaev honeycomb magnet $\alpha$-RuCl${}_3$ is studied for different directions of in-plane magnetic field using measurements of the magnetic Grüneisen parameter ${\Gamma }_B$ and specific heat $C$. We identify two critical fields $B_c^{AF1}$ and $B_c^{AF2}$ corresponding, respectively, to a transition between two magnetically ordered states and the loss of magnetic order toward a quantum paramagnetic state. The $B_c^{AF2}$ phase boundary reveals a narrow region of magnetic fields where inverse melting of the ordered phase may occur. No additional transitions are detected above $B_c^{AF2}$ for any direction of the in-plane field, although a shoulder anomaly in ${\Gamma }_B$ is observed systematically at $8-10$ T. Large field-induced entropy effects imply additional low-energy excitations at low fields and/or strongly field-dependent phonon entropies. Our results establish universal features of $\alpha$-RuCl${}_3$ in high magnetic fields and challenge the presence of a field-induced Kitaev spin liquid in this material.

4.5 pages + Supplemental Material

References in corpus (6)

• Models and Materials for Generalized Kitaev Magnetism
• Spin-wave excitations evidencing the Kitaev interaction in single crystalline $\alpha$-RuCl${}_3$
• Anisotropic Ru3+ 4d5 magnetism in the alpha-RuCl3 honeycomb system: susceptibility, specific heat and Zero field NMR
• Thermodynamic perspective on the field-induced behavior of $\alpha$-RuCl${}_3$
• Nature of Magnetic Excitations in the High-Field Phase of $\alpha$-RuCl${}_3$
• High-field thermal transport properties of the Kitaev quantum magnet alpha-RuCl3: evidence for low-energy excitations beyond the critical field

Cited by in corpus (6)

• Investigation of the magnetoelastic coupling anisotropy in the Kitaev material $\alpha$-RuCl${}_3$
• Neutron spectroscopy evidence for a possible magnetic-field-induced gapless quantum-spin-liquid phase in a Kitaev material $\alpha$-RuCl${}_3$
• Suppression of the antiferromagnetic order by Zn doping in a possible Kitaev material Na${}_2$Co${}_2$TeO${}_6$
• Signatures of a gapless quantum spin liquid in the Kitaev material Na${}_3$Co${}_{2-x}$Zn${}_x$SbO${}_6$
• Nesting instability of gapless U(1) spin liquids with spinon Fermi pockets in two dimensions
• The field-angle anisotropy of proximate Kitaev systems under an in-plane magnetic field