Spin-orbital-lattice entanglement in the ideal j=1/2 compound K${}_2$IrCl${}_6$

Abstract

Mott insulators with spin-orbit entangled j=1/2 moments host intriguing magnetic properties. The j=1/2 wave function requires cubic symmetry, while a noncubic crystal field mixes j=1/2 and 3/2 character. Spectroscopic studies of $5d^5$ iridates typically claim noncubic symmetry, e.g., based on a splitting of the excited j=3/2 quartet. A sizable splitting is particularly puzzling in antifluorite-type K${}_2$IrCl${}_6$, a frustrated fcc quantum magnet with global cubic symmetry. It raises the fundamental question about the stability of j=1/2 moments against magneto-elastic coupling. Combining resonant inelastic x-ray scattering with optical spectroscopy, we demonstrate that the multi-peak line shape in K${}_2$IrCl${}_6$ reflects a vibronic character of the j=3/2 states rather than a noncubic crystal field. The quasimolecular crystal structure with well separated IrCl${}_6$ octahedra explains the existence of well-defined sidebands that are usually smeared out in solids. Our results highlight the spin-orbital-lattice entangled character of cubic K${}_2$IrCl${}_6$ with ideal j=1/2 moments.

arXiv comment16 pages, 12 figures

References in corpus (63)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Resonant Inelastic X-ray Scattering Studies of Elementary Excitations
• Correlated quantum phenomena in the strong spin-orbit regime
• Kitaev quantum spin liquid - concept and materialization
• Spin-Orbit Physics Giving Rise to Novel Phases in Correlated Systems: Iridates and Related Materials
• Models and Materials for Generalized Kitaev Magnetism
• Isospin Dynamics in Sr2IrO4 : Forging Links to Cuprate Superconductivity
• Crystal field splitting and correlation effect on the electronic structure of A2IrO3
• Orbital effects in solids: basics, recent progress and opportunities
• Spin-controlled Mott-Hubbard bands in LaMnO_3 probed by optical ellipsometry
• Recent progress on correlated electron systems with strong spin-orbit coupling
• Fingerprints of spin-orbital physics in cubic Mott insulators: Magnetic exchange interactions and optical spectral weights
• Excitonic quasiparticles in a spin-orbit Mott insulator
• Giant Magnon Gap in Bilayer Iridate Sr3Ir2O7: Enhanced Pseudo-dipolar Interactions Near the Mott Transition
• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Testing the validity of the strong spin-orbit-coupling limit for octahedrally coordinated iridates in a model system Sr${}_3$CuIrO${}_6$
• Determining the Electron-Phonon Coupling Strength in Correlated Electron Systems from Resonant Inelastic X-ray Scattering
• Directly characterizing the relative strength and momentum dependence of electron-phonon coupling using resonant inelastic x-ray scattering
• Fingerprints of Kitaev physics in the magnetic excitations of honeycomb iridates
• Pseudo Jahn-Teller Effect and Magnetoelastic Coupling in Spin-Orbit Mott Insulators
• CaIrO3: a Spin-Orbit Mott Insulator Beyond the jeff = 1/2 Ground State
• Theory of optical spectral weights in Mott insulators with orbital degrees of freedom
• Resonant X-ray scattering and the $j_{\mathrm{eff}}=1/2$ electronic ground state in iridate perovskites
• Electron-lattice interactions strongly renormalize the charge transfer energy in the spin-chain cuprate Li${}_2$CuO${}_2$
• The Jahn-Teller effect and spin--orbit coupling: friends or foes?
• Optical study of orbital excitations in transition-metal oxides
• Spin-orbit entangled j=1/2 moments in Ba${}_2$CeIrO${}_6$ -- a frustrated fcc quantum magnet
• Confinement-Deconfinement Transition as an Indication of Spin-Liquid-Type Behavior in Na${}_2$IrO${}_3$
• Evidence of quantum dimer excitations in Sr${}_3$Ir${}_2$O${}_7$
• Charge-orbital-lattice coupling effects in the dd-excitation profile of one dimensional cuprates
• Electronic excitations in the edge-shared relativistic Mott insulator: Na${}_2$IrO${}_3$
• Mott-Hubbard exciton in the optical conductivity of YTiO3 and SmTiO3
• Cubic symmetry and magnetic frustration on the $fcc$ spin lattice in K${}_2$IrCl${}_6$
• Determining the Electron-Phonon Coupling in Superconducting Cuprates by Resonant Inelastic X-ray Scattering: Methods and Results on Nd${}_{1+x}$Ba${}_{2-x}$Cu${}_3$O${}_{7-\delta }$
• Anisotropic Optic Conductivities due to Spin and Orbital Orderings in LaVO3 and YVO3: First-Principles Studies
• Revisiting the Kitaev material candidacy of Ir4+ double perovskite iridates
• Degenerate manifolds, helimagnets, and multi-$\mathbf{Q}$ chiral phases in the classical Heisenberg antiferromagnet on the face-centered-cubic lattice
• Probing orbital fluctuations in RVO3 (R = Y, Gd, or Ce) by ellipsometry
• Dispersive Magnetic and Electronic Excitations in Iridate Perovskites Probed with Oxygen $K$-Edge Resonant Inelastic X-ray Scattering
• Jahn-Teller effect in systems with strong on-site spin-orbit coupling
• Nonmagnetic $J=0$ State and Spin-Orbit Excitations in K${}_2$RuCl${}_6$
• Collective orbital excitations in orbitally ordered YVO3 and HoVO3
• High-resolution resonant inelastic x-ray scattering study of the electron-phonon coupling in honeycomb $\alpha$-Li${}_2$IrO${}_3$
• Structural, electronic, and magnetic properties of nearly-ideal $J_{\mathrm{eff}}$ $=$ 1/2 iridium halides
• Generalization of the Franck-Condon model for phonon excitations by resonant inelastic X-ray scattering
• The origin of magnetism in a supposedly nonmagnetic osmium oxide
• Spin-orbit-lattice entangled state in A${}_2$MgReO${}_6$ (A = Ca, Sr, Ba) revealed by resonant inelastic X-ray scattering
• Multiple Spin-Orbit Excitons and the Electronic Structure of $\alpha$-RuCl${}_3$
• Toward cubic symmetry for Ir${}^{4+}$: structure and magnetism of antifluorite K${}_2$IrBr${}_6$
• Nearly itinerant electronic groundstate in the intercalated honeycomb iridate Ag${}_3$LiIr${}_2$O${}_6$
• A Hubbard exciton fluid in a photo-doped antiferromagnetic Mott insulator
• Magnon-spinon dichotomy in the Kitaev hyperhoneycomb $\beta$-Li${}_2$IrO${}_3$
• Possibility to realize spin-orbit-induced correlated physics in iridium fluorides
• Momentum-independent magnetic excitation continuum in the honeycomb iridate H${}_3$LiIr${}_2$O${}_6$
• Antiferromagnetic resonance in the cubic iridium hexahalides (NH${}_4$)${}_2$IrCl${}_6$ and K${}_2$IrCl${}_6$
• Vibronic excitations in resonant inelastic x-ray scattering spectra of K${}_2$RuCl${}_6$
• Magnetic excitations in double perovskite iridates La${}_2$$M$IrO${}_6$ ($M$ = Co, Ni, and Zn) mediated by 3$d$-5$d$ hybridization
• RIXS interferometry and the role of disorder in the quantum magnet Ba${}_3$Ti${}_{3-x}$Ir${}_x$O${}_9$
• Electronic excitations in $5d^4$ J=0 Os${}^{4+}$ halides studied by RIXS and optical spectroscopy
• Vibronic effect on resonant inelastic x-ray scattering in cubic iridium hexahalides
• Spin-orbit coupling in a half-filled $t_{2g}$ shell: the case of $5d^3$ K${}_2$ReCl${}_6$
• Spin-orbit coupling and crystal-field splitting in Ti-doped Ca2RuO4 studied by ellipsometry
• Rotational phase transitions in antifluorite-type osmate and iridate compounds

Cited by in corpus (3)

• Hidden orders in spin-orbit entangled correlated insulators
• Phonon-driven multipolar dynamics in a spin-orbit coupled Mott insulator
• Quasimolecular electronic structure of the trimer iridate Ba${}_4$NbIr${}_3$O${}_{12}$