ARPES study of the Kitaev Candidate $\alpha$-RuCl${}_3$

Abstract

$\alpha$-RuCl${}_3$ has been hinted as a spin-orbital-assisted Mott insulator in proximity to a Kitaev spin liquid state. Here we present ARPES measurements on single crystal $\alpha$-RuCl${}_3$ in both the pristine and electron-doped states, and combine them with LDA+SOC+U calculations performed for the several low-energy competing magnetically ordered states as well as the paramagnetic state. A large Mott gap is found in the measured band structure of the pristine compound that persists to more than 20 times beyond the magnetic ordering temperature, though the paramagnetic calculation shows almost no gap. Upon electron doping, spectral weight is transferred into the gap but the new states still maintain a sizable gap from the Fermi edge. These findings are most consistent with a Mott insulator with a somewhat exotic evolution out of the Mott state with both temperature and doping, likely related to unusually strong spin fluctuations.

arXiv comment5 pages, 6 figures in main text. 3 pages, 2 figures in supplementary information

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Cited by in corpus (40)

• Models and Materials for Generalized Kitaev Magnetism
• Phase Diagram of $\alpha$-RuCl${}_3$ in an in-plane Magnetic Field
• Theoretical investigation of the magnetic dynamics in $\alpha$-RuCl${}_3$
• Approximately quantized thermal Hall effect of chiral liquids coupled to phonons
• Electronic Structure of the Kitaev Material $\alpha$-${\text{RuCl}}_3$ Probed by Photoemission and Inverse Photoemission Spectroscopies
• Possible Structural Transformation and Enhanced Magnetic Fluctuations in Exfoliated $\alpha$-RuCl${}_3$
• Identification of Magnetic Interactions and High-field Quantum Spin Liquid in $\alpha$-RuCl${}_3$
• The range of non-Kitaev terms and fractional particles in RuCl${}_3$
• Electronically highly cubic conditions for Ru in alpha-RuCl3
• The Heart of Entanglement: Chiral, Nematic, and Incommensurate Phases in the Kitaev-Gamma Ladder in a Field
• Tensor network wavefunction of $S=1$ Kitaev spin liquids
• Electronic and magnetic properties of the RuX${}_3$ (X=Cl, Br, I) family: Two siblings -- and a cousin?
• Ordered states in the Kitaev-Heisenberg model: From 1D chains to 2D honeycomb
• Nonvanishing sub-gap photocurrent as a probe of lifetime effects
• Tunneling spectroscopy as a probe of fractionalization in 2D magnetic heterostructures
• Thermal Hall signatures of non-Kitaev spin liquids in honeycomb Kitaev materials
• Gapless Kitaev Spin Liquid to Classical String Gas through Tensor Networks
• Bond ordering and phase transitions in Na${}_2$IrO${}_3$ under high pressure
• Direct visualization of the charge transfer in Graphene/$\alpha$-RuCl${}_3$ heterostructure
• Local spin structure of the $\alpha$-RuCl${}_3$ honeycomb-lattice magnet observed via muon spin rotation/relaxation
• Tunneling spectroscopic signatures of charge doping and associated Mott transition in $\alpha$-RuCl${}_3$ in proximity to graphite
• Extent of frustration in the classical Kitaev-$\Gamma$ model via bond anisotropy
• Field-induced Kitaev multipolar liquid in spin-orbit coupled $d^2$ honeycomb Mott insulators
• Low temperature enhancement of ferromagnetic Kitaev correlations in α-RuCl3
• Ultrafast Spin Dynamics and Photoinduced Insulator-to-Metal Transition in $\alpha$-$RuC{l}_3$
• Incarnation of Majorana Fermions in Kitaev Quantum Spin Lattice
• Single-hole spectra of Kitaev spin liquids: from dynamical Nagaoka ferromagnetism to spin-hole fractionalization
• Electronic structure of $\mathbf{\alpha }$-RuCl${}_3$ by fixed-node and fixed-phase diffusion Monte Carlo methods
• Spin waves and stability of zigzag order in the Hubbard model with spin-dependent hopping terms - Application to the honeycomb lattice compounds $\mathrm{N}{\mathrm{a}}_2\mathrm{Ir}{\mathrm{O}}_3$ and $\alpha -\mathrm{RuC}{\mathrm{l}}_3$
• Dielectric Evidence for Possible Type-II Multiferroicity in alpha-RuCl3
• Insulator-to-metal Mott transition facilitated by lattice deformation in monolayer $\alpha$-RuCl${}_3$ on graphite
• Non-local features of the spin-orbit exciton in Kitaev materials
• Dynamics of a single hole in the Heisenberg-Kitaev model: a self-consistent Born approximation study
• Orbital-selective metal skin induced by alkali-metal-dosing Mott-insulating Ca${}_2$RuO${}_4$
• Mott Gap Softening Coinciding with Spin Correlations Collapse in a-RuCl3
• Electron quasi-itinerancy intertwined with quantum order by disorder in pyrochlore iridate magnetism
• Electronic transport mechanisms in a thin crystal of the Kitaev candidate $\alpha$-RuCl${}_3$ probed through guarded high impedance measurements
• Spin-phonon coupling and thermal Hall effect in the Kitaev model
• Direct Evidence for Fermi Statistics from Proximity to the Kitaev Spin Liquid in RuCl3
• Magnetic polarons due to spin-length fluctuations in ${\mathbf{d}}^4$ spin-orbit Mott systems