High-Field Quantum Disordered State in $\alpha$-RuCl3: Spin Flips, Bound States, and a Multi-Particle Continuum

Abstract

Layered $\alpha$-RuCl3 has been discussed as a proximate Kitaev spin liquid compound. Raman and THz spectroscopy of magnetic excitations confirm that the low-temperature antiferromagnetic ordered phase features a broad Raman continuum, together with two magnon-like excitations at 2.7 and 3.6 meV, respectively. The continuum strength is maximized as long-range order is suppressed by an external magnetic field. The state above the field-induced quantum phase transition around 7.5 T is characterized by a gapped multi-particle continuum out of which a two-particle bound state emerges, together with a well-defined single-particle excitation at lower energy. Exact diagonalization calculations demonstrate that Kitaev and off-diagonal exchange terms in the Fleury-Loudon operator are crucial for the occurrence of these features in the Raman spectra. Our study firmly establishes the partially-polarized quantum disordered character of the high-field phase.

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Cited by in corpus (50)

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• Phonon dynamics in the Kitaev spin liquid
• Thermodynamic perspective on the field-induced behavior of $\alpha$-RuCl${}_3$
• Magnetic anisotropy reversal driven by structural symmetry-breaking in monolayer α-RuCl3
• Giant magnetic in-plane anisotropy and competing instabilities in Na3Co2SbO6
• Nature of Magnetic Excitations in the High-Field Phase of $\alpha$-RuCl${}_3$
• Electrical Access to Ising Anyons in Kitaev Spin Liquids
• The Heart of Entanglement: Chiral, Nematic, and Incommensurate Phases in the Kitaev-Gamma Ladder in a Field
• Magnetoelastic coupling and effects of uniaxial strain in $\alpha$-RuCl${}_3$ from first principles
• Field-induced phase transitions of the Kitaev material $\alpha$-RuCl${}_3$ probed by thermal expansion and magnetostriction
• Electronic and magnetic properties of the RuX${}_3$ (X=Cl, Br, I) family: Two siblings -- and a cousin?
• Disorder upon disorder: localization effects in the Kitaev spin liquid
• Angle-dependent thermodynamics of $\alpha$-RuCl${}_3$
• Time-Domain Terahertz Spectroscopy in High Magnetic Fields
• Magnetic excitations of the field induced states in BaCo2(AsO4)2 probed by time-domain terahertz spectroscopy
• Kitaev Quantum Spin Liquids
• High-field thermal transport properties of the Kitaev quantum magnet alpha-RuCl3: evidence for low-energy excitations beyond the critical field
• Kitaev magnetism through the prism of lithium iridate
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