Orbital reconstruction in nonpolar tetravalent transition-metal oxide layers

Abstract

A promising route to tailoring the electronic properties of quantum materials and devices rests on the idea of orbital engineering in multilayered oxide heterostructures. Here we show that the interplay of interlayer charge imbalance and ligand distortions provides a knob for tuning the sequence of electronic levels even in intrinsically stacked oxides. We resolve in this regard the $d$-level structure of layered Sr${}_2$IrO${}_4$ by electron spin resonance. While canonical ligand-field theory predicts $g_{\parallel }$-factors $<2$ for positive tetragonal distortions as present in Sr${}_2$IrO${}_4$, the experiment indicates $g_{\parallel }>2$. This implies that the iridium $d$ levels are inverted with respect to their normal ordering. State-of-the-art electronic-structure calculations confirm the level switching in Sr${}_2$IrO${}_4$, whereas we find them in Ba${}_2$IrO${}_4$ to be instead normally ordered. Given the nonpolar character of the metal-oxygen layers, our findings highlight the tetravalent transition-metal 214 oxides as ideal platforms to explore $d$-orbital reconstruction in the context of oxide electronics.

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• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Isospin Dynamics in Sr2IrO4 : Forging Links to Cuprate Superconductivity
• Theory of the field-induced gap in $S=1/2$ antiferromagnetic chains
• Fermi Arcs in a Doped Pseudospin-1/2 Heisenberg Antiferromagnet
• Kitaev interactions between j=1/2 moments in honeycomb Na2IrO3 are large and ferromagnetic: insights from ab initio quantum chemistry calculations
• Orbital reflectometry
• The magnetic and crystal structures of Sr2IrO4: A neutron diffraction study
• Excitonic quasiparticles in a spin-orbit Mott insulator
• Robustness of basal-plane antiferromagnetic order and the $J_{eff}=1/2$ state in single-layer iridate spin-orbit Mott insulators
• Testing the validity of the strong spin-orbit-coupling limit for octahedrally coordinated iridates in a model system Sr${}_3$CuIrO${}_6$
• Orbital Dependent Phase Control in Ca2-xSrxRuO4
• Slaving of the magnetic moment canting to the correlated oxygen rotation in Sr2IrO4 revealed by X-ray resonant scattering
• Magnetic couplings, optical spectra, and spin-orbit exciton in 5d electron Mott insulator Sr2IrO4
• Topological states in pyrochlore iridates: long-range anisotropy strongly competing with spin-orbit interaction
• Magnetic state of pyrochlore Cd2Os2O7 emerging from strong competition of ligand distortions and longer-range crystalline anisotropy
• Tuning Magnetic Coupling in Sr${}_2$IrO${}_4$ Thin Films with Epitaxial Strain
• Low energy magnetic excitations in the spin-orbital Mott insulator Sr${}_2$IrO${}_4$
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Cited by in corpus (47)

• Models and Materials for Generalized Kitaev Magnetism
• Spin-orbit excitation energies, anisotropic exchange, and magnetic phases of honeycomb RuCl3
• Pressure-induced dimerization and valence bond crystal formation in the Kitaev-Heisenberg magnet alpha-RuCl3
• Square Lattice Iridates
• Pseudo Jahn-Teller Effect and Magnetoelastic Coupling in Spin-Orbit Mott Insulators
• Pressure-tuned magnetic interactions in honeycomb Kitaev materials
• Giant magnetic response of a two-dimensional antiferromagnet
• Strong effect of hydrogen order on magnetic Kitaev interactions in H${}_3$LiIr${}_2$O${}_6$
• Unraveling the nature of magnetism of the 5${\mathbf{d}}^4$ double perovskite Ba${}_2$YIrO${}_6$
• Magnetic excitations and electronic interactions in Sr${}_2$CuTeO${}_6$: a spin-1/2 square lattice Heisenberg antiferromagnet
• The vicinity of hyper-honeycomb $\beta$-Li2IrO3 to a three-dimensional Kitaev spin liquid state
• Non-collinear antiferromagnetism of coupled spins and pseudospins in the double perovskite La2CuIrO6
• Dimensionality-strain phase diagram of strontium iridates
• New Honeycomb Iridium (V) Oxides: NaIrO${}_3$ and Sr${}_3$CaIr${}_2$O${}_9$
• Single-site magnetic anisotropy governed by inter-layer cation charge imbalance in triangular-lattice AYbX${}_2$
• Jahn-Teller effect in systems with strong on-site spin-orbit coupling
• Validity and limitations of the superexchange model for the magnetic properties of Sr2IrO4 and Ba2IrO4 mediated by the strong spin-orbit coupling
• First-Principles Calculation of Spin and Orbital Contributions to Magnetically Ordered Moments in Sr${}_2$IrO${}_4$
• Covalency and vibronic couplings make a nonmagnetic j=3/2 ion magnetic
• Long-range interactions in the effective low energy Hamiltonian of Sr2IrO4: a core level resonant inelastic x-ray scattering study
• Heavy-mass magnetic modes in pyrochlore iridates due to dominant Dzyaloshinskii-Moriya interaction
• Spin orientations of the spin-half Ir4+ ions in Sr3NiIrO6, Sr2IrO4 and Na2IrO3: Density functional, perturbation theory and Madelung potential analyses
• Toward cubic symmetry for Ir${}^{4+}$: structure and magnetism of antifluorite K${}_2$IrBr${}_6$
• Probing the $J_{eff}=0$ ground state and the Van Vleck paramagnetism of the Ir${}^{5+}$ ions in the layered Sr${}_2$Co${}_{0.5}$Ir${}_{0.5}$O${}_4$
• ARPES study of orbital characters, symmetry breakings and pseudogaps in doped and pure Sr2IrO4
• Zeeman interaction and Jahn-Teller effect in ${\Gamma }_8$ multiplet
• Magnetic properties of bilayer Sr${}_3$Ir${}_2$O${}_7$: role of epitaxial strain and oxygen vacancies
• Magnetization density distribution of Sr${}_2$IrO${}_4$: Deviation from a local $j_{\text{eff}}=1/2$ picture
• Anomalous Magnetoresistance due to Longitudinal Spin Fluctuations in a Jeff = 1/2 Mott Semiconductor
• NaRuO${}_2$: Kitaev-Heisenberg exchange in triangular-lattice setting
• Orbiton-Phonon coupling in Ir5+(5d4) double perovskite Ba2YIrO6
• Electronic and structural properties of RbCeX${}_2$ (X${}_2$: O${}_2$, S${}_2$, SeS, Se${}_2$, TeSe, Te${}_2$)
• $\tilde{J}$-pseudospin states and the crystal field of cubic systems
• Large off diagonal exchange couplings and spin liquid states in ${\mathbf{C}}_3$ symmetric iridates
• Energy scales in 4f1 delafossite magnets: crystal-field splittings larger than the strength of spin-orbit coupling in KCeO2
• Superexchange interactions between spin-orbit-coupled $j\approx 1/2$ ions in oxides with face-sharing ligand octahedra
• Direct observation of oxygen polarization in Sr${}_2$IrO${}_4$ by O $K$-edge x-ray magnetic circular dichroism
• Influence of multiplet structure on photoemission spectra of spin-orbit driven Mott insulators: application to $\mathbf{S}{\mathbf{r}}_2\mathbf{Ir}{\mathbf{O}}_4$
• Crystal-field effects competing with spin-orbit interactions in NaCeO${}_2$
• Critical fluctuations in the spin-orbit Mott insulator Sr${}_3$Ir${}_2$O${}_7$
• Sweet spot in the RuCl${}_3$ magnetic system: nearly ideal $j_{\mathrm{eff}}=1/2$ moments and maximized $K/J$ ratio under pressure
• Anisotropic Coulomb exchange as source of Kitaev and off-diagonal symmetric anisotropic couplings
• The rich phase diagram of the prototypical iridate Ba${}_2$IrO${}_4$: Effective low-energy models and metal-insulator transition
• Interplay of electron correlations, spin-orbit couplings, and structural effects for Cu centers in the quasi-two-dimensional magnet InCu${}_{2/3}$V${}_{1/3}$O${}_3$
• Magnetism in artificial Ruddlesden-Popper iridates leveraged by structural distortions
• More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions
• Relevance of on-site and intersite Coulomb interactions in the Kitaev-Heisenberg magnet Na${}_3$Co${}_2$SbO${}_6$