Majorana-fermion origin of the planar thermal Hall effect in the Kitaev magnet $\alpha$-RuCl${}_3$

Abstract

The field-induced quantum disordered state of layered honeycomb magnet $\alpha$-RuCl${}_3$ is a prime candidate for Kitaev spin liquids hosting Majorana fermions and non-Abelian anyons. Recent observations of anomalous planar thermal Hall effect demonstrate a topological edge mode, but whether it originates from Majorana fermions or bosonic magnons remains controversial. Here we distinguish these origins from low-temperature measurements of high-resolution specific heat and thermal Hall conductivity with rotating in-plane fields. In the honeycomb bond direction, a distinct closure of the low-energy bulk gap is observed concomitantly with the sign reversal of the Hall effect. General discussions of topological bands show that this is the hallmark of an angle-rotation-induced topological transition of fermions, providing conclusive evidence for the Majorana-fermion origin of the thermal Hall effect in $\alpha$-RuCl${}_3$.

21 pages, 7 figures

References in corpus (15)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Successive magnetic phase transitions in $\mathbf{\alpha }$-RuCl${}_3$: XY-like frustrated magnet on the honeycomb lattice
• Half-integer quantized anomalous thermal Hall effect in the Kitaev material $\alpha$-RuCl${}_3$
• Robustness of the thermal Hall effect close to half-quantization in a field-induced spin liquid state
• The planar thermal Hall conductivity in the Kitaev magnet α-RuCl3
• Sample dependence of the half-integer quantized thermal Hall effect in the Kitaev candidate $\alpha$-RuCl${}_3$
• Proximate ferromagnetic state in the Kitaev model material $\alpha$-RuCl${}_3$
• Sign structure of thermal Hall conductivity for in-plane-field polarized Kitaev magnets
• Unconventional spin dynamics in the honeycomb-lattice material $\alpha$-RuCl${}_3$: high-field ESR studies
• Topological magnons for thermal Hall transport in frustrated magnets with bond-dependent interactions
• Identification of a Kitaev Quantum Spin Liquid by Magnetic Field Angle Dependence
• Origin of oscillatory structures in the magnetothermal conductivity of the putative Kitaev magnet $\alpha$-RuCl${}_3$
• Symmetry-based requirement for the measurement of electrical and thermal Hall conductivity under an in-plane magnetic field
• The sample-dependent and sample-independent thermal transport properties of $\alpha$-RuCl${}_3$
• Field-angle dependence of thermal Hall conductivity in magnetically ordered Kitaev-Heisenberg system

Cited by in corpus (16)

• Kitaev Quantum Spin Liquids
• Two-step growth of high-quality single crystals of the Kitaev magnet $\alpha$-RuCl${}_3$
• Magnetothermal transport in ultraclean single crystals of Kitaev magnet $\alpha$-RuCl${}_3$
• Thermal Transport Properties of Magnons on the $\alpha$-T${}_3$ Lattice
• Field-Angle-Resolved Specific Heat in Na${}_2$Co${}_2$TeO${}_6$: Evidence against Kitaev Quantum Spin Liquid
• Lifting of gap nodes by disorder in ultranodal superconductor candidate FeSe1-xSx
• Digital Quantum Simulation of the Kitaev Quantum Spin Liquid
• Bulk excitations in ultraclean $\alpha$-RuCl${}_3$: Quantitative evidence for Majorana dispersions in a Kitaev quantum spin liquid
• Quantum Spin Liquid phases in Kitaev Materials
• A primer on Kitaev Model: Basic aspects, material realization, and recent experiments
• Angular-Dependent Thermal Hall Effect in a Honeycomb Magnet: Disentangling Kitaev and Dzyaloshinskii-Moriya Interactions
• Robustness of Vacancy-Bound Non-Abelian Anyons in the Kitaev Model in a Magnetic Field
• Spin-phonon coupling and thermal Hall effect in the Kitaev model
• Vector pulse magnet
• Tuning the Chern number of Kitaev quantum spin liquid
• Anomalies in the thermal conductivity of honeycomb antiferromagnet MnPS${}_3$