Giant Magnon Gap in Bilayer Iridate Sr3Ir2O7: Enhanced Pseudo-dipolar Interactions Near the Mott Transition

Abstract

Using resonant inelastic x-ray scattering, we observe in the bilayer iridate Sr3Ir2O7, a spin-orbit coupling driven magnetic insulator with a small charge gap, a magnon gap of ~92 meV for both acoustic and optical branches. This exceptionally large magnon gap exceeds the total magnon bandwidth of ~70 meV and implies a marked departure from the Heisenberg model, in stark contrast to the case of the single-layer iridate Sr2IrO4. Analyzing the origin of these observations, we find that the giant magnon gap results from bond-directional pseudo-dipolar interactions that are strongly enhanced near the metal-insulator transition boundary. This suggests that novel magnetism, such as that inspired by the Kitaev model built on the pseudo-dipolar interactions, may emerge in small charge-gap iridates.

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• The Challenge of Spin-Orbit-Tuned Ground States in Iridates
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• Spin-orbit-entangled electronic phases in 4$d$ and 5$d$ transition-metal compounds
• Hexagonal Perovskites as Quantum Materials
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• A New Type of Quantum Criticality in the Pyrochlore Iridates
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• Magnetic excitation spectrum of Na2IrO3 probed with resonant inelastic x-ray scattering
• Mixing of $t_{2g}$-$e_g$ orbitals in 4d and 5d transition metal oxides
• Emergent excitation at the magnetic metal-insulator transition in the pyrochlore osmate Cd2Os2O7
• CaIrO3: a Spin-Orbit Mott Insulator Beyond the jeff = 1/2 Ground State
• Insights into the High Temperature Superconducting Cuprates from Resonant Inelastic X-ray Scattering
• Coulomb Correlations in 4d and 5d Oxides from First Principles - or How Spin-Orbit Materials choose their Effective Orbital Degeneracies
• Two-magnon Raman scattering and pseudospin-lattice interactions in Sr2IrO4 and Sr3Ir2O7
• Resonant X-ray scattering and the $j_{\mathrm{eff}}=1/2$ electronic ground state in iridate perovskites
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• Dynamical structure factors and excitation modes of the bilayer Heisenberg model
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• A charge density wave-like instability in a doped spin-orbit-assisted weak Mott insulator
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• First-order melting of a weak spin-orbit Mott insulator into a correlated metal
• Pressure-Induced Confined Metal from the Mott Insulator Sr3Ir2O7
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• A weakly correlated Fermi liquid state with a small Fermi surface in lightly doped Sr${}_3$Ir${}_2$O${}_7$
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• Structural investigation of the bilayer iridate Sr3Ir2O7
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• Exploring Quantum Materials with Resonant Inelastic X-Ray Scattering
• Laser-Induced Transient Magnons in Sr3Ir2O7 Throughout the Brillouin Zone
• Dispersive Magnetic and Electronic Excitations in Iridate Perovskites Probed with Oxygen $K$-Edge Resonant Inelastic X-ray Scattering
• Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr${}_{1-x}$La${}_x$)${}_3$Ir${}_2$O${}_7$
• Novel spin-orbit coupling driven emergent states in iridate-based heterostructures
• $J_{eff}=1/2$ Mott Insulating State in Rh and Ir Fluorides
• Magnetic excitation spectra in pyrochlore iridates
• Microscopic theory of magnetism in Sr3Ir2O7
• The trimer-based spin liquid candidate Ba4NbIr3O12
• Correlated Quantum Phenomena of Spin-Orbit Coupled Perovskite Oxide Heterostructures: Cases of SrRuO3 and SrIrO3-Based Artificial Superlattices
• Antiferromagnetic Excitonic Insulator State in Sr3Ir2O7
• Lattice frustration in spin-orbit Mott insulator Sr3Ir2O7 at high pressure
• Magnetic excitations in a three-orbital model for the strongly spin-orbit coupled iridates: Effect of mixing between the J=1/2 and 3/2 sectors
• Magnetic properties of bilayer Sr${}_3$Ir${}_2$O${}_7$: role of epitaxial strain and oxygen vacancies
• Anisotropic interactions opposing magnetocrystalline anisotropy in Sr${}_3$NiIrO${}_6$
• Resonant Inelastic X-Ray Scattering as a Probe of the Phase and Excitations of the Order Parameter of Superconductors
• Disordered dimer state in electron-doped Sr${}_3$Ir${}_2$O${}_7$
• Probing single magnon excitations in Sr${}_2$IrO${}_4$ using O $K$-edge resonant inelastic X-ray scattering
• Description of resonant inelastic x-ray scattering in correlated metals
• Anomalous Magnetoresistance due to Longitudinal Spin Fluctuations in a Jeff = 1/2 Mott Semiconductor
• Magnetic Fluctuations and the Spin-Orbit Interaction in Mott Insulating CoO
• Spin-orbital excitons and their potential condensation in pentavalent iridates
• Sr${}_2$IrO${}_4$/Sr${}_3$Ir${}_2$O${}_7$ superlattice for a model 2D quantum Heisenberg antiferromagnet
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• Symmetry-resolved two-magnon excitations in a strong spin-orbit-coupled bilayer antiferromagnet
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• Resonant inelastic x-ray scattering of magnetic excitations under pressure
• Resonant inelastic x-ray scattering on single-magnons at oxygen $K$-edges
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• Stable Higgs mode in anisotropic quantum magnets
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• Electronic and optical properties of La-doped Sr${}_3$Ir${}_2$O${}_7$ epitaxial thin-films
• Magnetic excitations in Nd${}_{n+1}$Ni${}_n$O${}_{3n+1}$ Ruddlesden-Popper nickelates observed via resonant inelastic x-ray scattering
• Reconciling monolayer and bilayer $J_{\mathrm{eff}}=1/2$ square lattices in hybrid oxide superlattice
• Effect of broken symmetry on resonant inelastic x-ray scattering from undoped cuprates
• Observation of excitons bound by antiferromagnetic correlations
• Critical fluctuations in the spin-orbit Mott insulator Sr${}_3$Ir${}_2$O${}_7$
• A $j_{\mathrm{eff}}=1/2$ pseudospinon continuum in CaIrO${}_3$
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• Coexistence of insulator-like paramagnon and metallic spin-orbit exciton modes in SrIrO${}_3$
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• Magnetic excitations of Sr${}_3$Ir${}_2$O${}_7$ observed by inelastic neutron scattering measurement
• BCS-BEC Crossover of Triplet Exciton Condensation in Bilayer Systems