Electronic Structure of the Kitaev Material $\alpha$-${\text{RuCl}}_3$ Probed by Photoemission and Inverse Photoemission Spectroscopies

Abstract

Recently, $\alpha$-${\text{RuCl}}_3$ has attracted much attention as a possible material realization of the honeycomb Kitaev model, which may stabilize a quantum-spin-liquid state. Compared to extensive studies on its magnetic properties, there is still a lack of understanding on its electronic structure, which is strongly related with its Kitaev physics. Here, the electronic structure of $\alpha$-${\text{RuCl}}_3$ is investigated by photoemission (PE) and inverse photoemission (IPE) spectroscopies. The band gap, directly measured from PE/IPE spectra, is found to be 1.9 eV, much larger than previous estimations. The LDA calculations show that the on-site Coulomb interaction $\text{U}$ can open the band gap without spin-orbit coupling (SOC). However, the SOC should also be incorporated to reproduce the proper gap size, indicating that the interplay between $\text{U}$ and SOC plays an essential role in the physics of $\alpha$-${\text{RuCl}}_3$. There exist some spectral features in PE/IPE spectra which cannot be explained by the LDA calculations. To explain such discrepancies, we perform the configuration-interaction calculations for a ${\text{RuCl}}_6^{3-}$ cluster. The experimental data and calculations demonstrate that the 4$\text{d}$ compound $\alpha$-${\text{RuCl}}_3$ is a $J_{\text{eff}}$ = 1/2 Mott insulator rather than a quasimolecular-orbital insulator. Our study also provides important physical parameters, required in verifying the proposed Kitaev physics in $\alpha$-${\text{RuCl}}_3$.

arXiv comment22 pages, 4 figures

References in corpus (24)

• Anyons in an exactly solved model and beyond
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Kitaev-Heisenberg Model on Honeycomb Lattice: Possible Exotic Phases in Iridium Oxides $A_2$IrO${}_3$
• $\alpha$-RuCl3: a Spin-Orbit Assisted Mott Insulator on a Honeycomb Lattice
• Relevance of the Heisenberg-Kitaev model for the honeycomb lattice iridates A_2IrO_3
• Generic spin model for the honeycomb iridates beyond the Kitaev limit
• Spin waves and revised crystal structure of honeycomb iridate Na2IrO3
• On the Origin of Zigzag Magnetic Order in Iridium Oxide Na2IrO3
• The monoclinic crystal structure of $\alpha$-RuCl${}_3$ and the zigzag antiferromagnetic ground state
• Scattering Continuum and Possible Fractionalized Excitations in $\alpha$-RuCl${}_3$
• Magnetic order in $\alpha$-RuCl${}_3$: a honeycomb lattice quantum magnet with strong spin-orbit coupling
• Low-temperature crystal and magnetic structure of $\alpha$-RuCl3
• Kitaev magnetism in honeycomb RuCl3 with intermediate spin-orbit coupling
• Fermionic response from fractionalization in an insulating two-dimensional magnet
• Crystal structure and magnetism in $\alpha$-RuCl3: an ab-initio study
• Hidden symmetries of the extended Kitaev-Heisenberg model: Implications for honeycomb lattice iridates A2IrO3
• Na2IrO3 as a molecular orbital crystal
• Spin-orbit excitations and electronic structure of the putative Kitaev magnet $\alpha$-RuCl${}_3$
• J${}_{eff}$ description of the honeycomb Mott insulator $\alpha$-RuCl${}_3$
• Origin of the insulating state in honeycomb iridates and rhodates
• ARPES study of the Kitaev Candidate $\alpha$-RuCl${}_3$
• Electronic excitations in the edge-shared relativistic Mott insulator: Na${}_2$IrO${}_3$
• From a quasimolecular band insulator to a relativistic Mott insulator in $t_{2g}^5$ systems with a honeycomb lattice structure
• Exciton doublet in the Mott-Hubbard LiCuVO${}_4$ insulator identified by spectral ellipsometry

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• Models and Materials for Generalized Kitaev Magnetism
• Hunting Majorana Fermions in Kitaev Magnets
• Phase Diagram of $\alpha$-RuCl${}_3$ in an in-plane Magnetic Field
• Field-induced quantum criticality in the Kitaev system $\alpha$-RuCl${}_3$
• Layer- and doping-tunable long range ferromagnetic order-ing in two-dimensional CrS2
• Theoretical investigation of the magnetic dynamics in $\alpha$-RuCl${}_3$
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• Electronic and phonon excitations in α-RuCl${}_3$
• Field-induced phase transitions of the Kitaev material $\alpha$-RuCl${}_3$ probed by thermal expansion and magnetostriction
• Polarization-resolved Raman spectroscopy of α-RuCl3 and evidence of room temperature two-dimensional magnetic scattering
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• Multiple Spin-Orbit Excitons and the Electronic Structure of $\alpha$-RuCl${}_3$
• Direct visualization of the charge transfer in Graphene/$\alpha$-RuCl${}_3$ heterostructure
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• Contrasting electronic states of RuI3 and RuCl3
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• Toward improved property prediction of 2D materials using many-body quantum Monte Carlo methods
• Ground-State Phase Diagram of the Kitaev-Heisenberg Model on a Three-dimensional Hyperhoneycomb Lattice
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• Insulator-to-metal Mott transition facilitated by lattice deformation in monolayer $\alpha$-RuCl${}_3$ on graphite
• Nonequilibrium dynamics of $\alpha$-RuCl${}_3$ -- a time-resolved magneto-optical spectroscopy study
• From linear to circular polarized light -- Floquet engineering in Kitaev-Heisenberg materials with Lissajous figures
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• Possible Realization of Kitaev Spin Liquids in van der Waals Heterostructures of $\alpha$-RuCl${}_3$ and Cr$X_3$ ($X$=Cl and I)
• Mott Gap Softening Coinciding with Spin Correlations Collapse in a-RuCl3
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• Electronic transport mechanisms in a thin crystal of the Kitaev candidate $\alpha$-RuCl${}_3$ probed through guarded high impedance measurements
• Schwinger boson theory for $S=1$ Kitaev quantum spin liquids
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• Strain-induced Landau levels of Majorana fermions in an anisotropically interacting Kitaev model on a honeycomb lattice
• Spin-phonon coupling and thermal Hall effect in the Kitaev model
• Magnetic field effects on the Kitaev model coupled to environment
• Vortex creation and control in the Kitaev spin liquid by local bond modulations