Scattering Continuum and Possible Fractionalized Excitations in $\alpha$-RuCl${}_3$

Abstract

The combination of electronic correlation and spin-orbit coupling is thought to precipitate a variety of highly unusual electronic phases in solids, including topological and quantum spin liquid states. We report a Raman scattering study that provides evidence for unconventional excitations in $\alpha$-RuCl${}_3$, a spin-orbit coupled Mott insulator on the honeycomb lattice. In particular, our measurements reveal unusual magnetic scattering, typified by a broad continuum. The temperature dependence of this continuum is evident over a large scale compared to the magnetic ordering temperature, suggestive of frustrated magnetic interactions. This is confirmed through an analysis of the phonon linewidths, which show a related anomaly due to spin-phonon coupling. These observations are in line with theoretical expectations for the Heisenberg-Kitaev model and suggest that $\alpha$-RuCl${}_3$ may be close to a quantum spin liquid ground state.

7 pages, 3 figures, Supplemental Material included

References in corpus (6)

• Non-Abelian Anyons and Topological Quantum Computation
• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Crystal field splitting and correlation effect on the electronic structure of A2IrO3
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Cited by in corpus (20)

• Models and Materials for Generalized Kitaev Magnetism
• Magnetic order in $\alpha$-RuCl${}_3$: a honeycomb lattice quantum magnet with strong spin-orbit coupling
• Spin-wave excitations evidencing the Kitaev interaction in single crystalline $\alpha$-RuCl${}_3$
• Magnetic Excitations and Continuum of a Field-Induced Quantum Spin Liquid in $\alpha$-RuCl${}_3$
• Microscopic mechanism for higher-spin Kitaev model
• Theory of the field-revealed Kitaev spin liquid
• Raman spectroscopic signature of fractionalized excitations in the harmonic-honeycomb iridates $\beta$- and $\gamma$-Li${}_2$IrO${}_3$
• Spin-split band hybridization in graphene proximitized with $\alpha$-RuCl${}_3$ nanosheets
• Electronic Structure of the Kitaev Material $\alpha$-${\text{RuCl}}_3$ Probed by Photoemission and Inverse Photoemission Spectroscopies
• Rearrangement of Van-der-Waals Stacking and Formation of a Singlet State at $T=90$ K in a Cluster Magnet
• High-pressure magnetization and NMR studies on $\alpha$-RuCl${}_3$
• Electronic and phonon excitations in α-RuCl${}_3$
• Spin waves and spin-state transitions in a ruthenate high-temperature antiferromagnet
• Crystalline Kitaev spin liquids
• Thermal transport in a two-dimensional ${\mathbb{Z}}_2$ spin liquid
• Revisiting the Kitaev material candidacy of Ir4+ double perovskite iridates
• Temperature evolution of spin dynamics in two- and three-dimensional Kitaev models: Influence of fluctuating gauge fluxes
• Probing spinon nodal structures in three-dimensional Kitaev spin liquids
• Putative spin liquid in the triangle-based iridate Ba${}_3$IrTi${}_2$O${}_9$
• Incarnation of Majorana Fermions in Kitaev Quantum Spin Lattice