THz excitations in α-RuCl3: Majorana fermions, rigid-plane shear and compression modes

Abstract

Spin liquids may host emergent quasiparticles, collective excitations of the spin degrees of freedom with characteristic features of Majorana fermions, which experimentally are detectable by broad excitation continua due to spin fractionalization. The latter is predicted for the Kitaev spin liquid, an exactly solvable model with bond-dependent interactions on a two-dimensional honeycomb lattice. Here we report on detailed THz experiments in α-RuCl3, identifying these characteristic fingerprints of Majorana fermions. The continuum intensity decreases and finally vanishes on increasing temperature. It partly overlaps with phonon modes representing characteristic sliding and compression modes of the van der Waals bonded molecular layers.

6 pages, 4 figures

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• Electronic and phonon excitations in α-RuCl${}_3$
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• Probing spinon nodal structures in three-dimensional Kitaev spin liquids
• Mechanism for subgap optical conductivity in honeycomb Kitaev materials
• Sub-gap optical response across the structural phase transition in van der Waals layered α-RuCl${}_3$

Cited by in corpus (13)

• Hunting Majorana Fermions in Kitaev Magnets
• Dynamical and thermal magnetic properties of the Kitaev spin liquid candidate $\alpha$-RuCl${}_3$
• High-Field Quantum Disordered State in $\alpha$-RuCl3: Spin Flips, Bound States, and a Multi-Particle Continuum
• A magnetic continuum observed by terahertz spectroscopy in a quantum spin liquid candidate BaCo${}_2$(AsO${}_4$)${}_2$
• Unusual heat transport of the Kitaev material Na${}_2$Co${}_2$TeO${}_6$: putative quantum spin liquid and low-energy spin excitations
• Giant Phonon Anomalies in the Proximate Kitaev Quantum Spin Liquid $\alpha$-RuCl${}_3$
• Phonon renormalization in the Kitaev quantum spin liquid
• Two-dimensional natural hyperbolic materials: From polaritons modulation to applications
• Kitaev Quantum Spin Liquids
• Extraction of the interaction parameters for $\alpha -$RuCl${}_3$ from neutron data using machine learning
• Field evolution of low-energy excitations in the hyperhoneycomb magnet $\beta$-Li${}_2$IrO${}_3$
• Mott Gap Softening Coinciding with Spin Correlations Collapse in a-RuCl3
• The Role of the Third Dimension in Searching Majorana Fermions in $\alpha$-RuCl${}_3$ via Phonons