Orbital Dependent Phase Control in Ca2-xSrxRuO4

Abstract

We present first-principles studies on the orbital states of the layered perovskites Ca${}_{2-x}$Sr${}_x$RuO${}_4$. The crossover from antiferromagnetic (AF) Mott insulator for $x<0.2$ to nearly ferromagnetic (FM) metal at $x=0.5$ is characterized by the systematic change of the $xy$ orbital occupation. For the AF side ($x<0.2$), we present firm evidence for the $xy$ ferro-orbital ordering. It is found that the degeneracy of $t_{2g}$ (or $e_g$) states is lifted robustly due to the two-dimensional (2D) crystal-structure, even without the Jahn-Teller distortion of RuO${}_6$. This effect dominates, and the cooperative occupation of $xy$ orbital is concluded. In contrast to recent proposals, the resulting electronic structure explains well both the observed X-ray absorption spectra and the double peak structure of optical conductivity. For the FM side ($x=0.5$), however, the $xy$ orbital with half filling opens a pseudo-gap in the FM state and contributes to the spin $S$=1/2 moment (rather than $S$=1 for $x$=0.0 case) dominantly, while $yz,zx$ states are itinerant with very small spin polarization, explaining the recent neutron data consistently.

17 pages, 5 figures

References in corpus (7)

• Electronic structure and magnetism in Ru based perovskites
• Ferromagnetic spin fluctuation induced superconductivity in Sr_2RuO_4
• Magnetic Phase Diagram of Ca2-xSrxRuO4 Governed by Structural Distortions
• Prediction of Orbital Ordering in Single-Layered Ruthenates
• Electron and orbital correlations in Ca_{2-x}Sr_{x}RuO_{4} probed by optical spectroscopy
• Anisotropic Optic Conductivities due to Spin and Orbital Orderings in LaVO3 and YVO3: First-Principles Studies
• Anomalous spin density distribution on oxygen and Ru in Ca${}_{1.5}$Sr${}_{0.5}$RuO${}_4$: A polarised neutron diffraction study

Cited by in corpus (66)

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• Temperature and bath size in exact diagonalization dynamical mean field theory
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• Novel Mott Transitions in Non-Isotropic Two-Band Hubbard Model
• Spin, charge and orbital fluctuations in a multi-orbital Mott insulator
• Orbital ordering transition in Ca${}_2$RuO${}_4$ observed with resonant x-ray diffraction
• Subband filling and Mott transition in Ca_{2-x}Sr_xRuO_4
• Mechanism of hopping transport in disordered Mott insulators
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• Highly anisotropic magnon dispersion in Ca2RuO4: evidence for strong spin orbit coupling
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• Tuning a Strain-Induced Orbital Selective Mott Transition in Epitaxial VO${}_2$
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• Orbitally-driven Behavior: Mott Transition, Quantum Oscillations and Colossal Magnetoresistance in Bilayered Ca3Ru2O7
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• Magnetic excitations in the metallic single-layer Ruthenates Ca(2-x)Sr(x)RuO(4) studied by inelastic neutron scattering
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• Dynamical cluster approximation study of the anisotropic two-orbital Hubbard model
• Electron-lattice coupling, orbital stability and the phase diagram of Ca${}_{2-x}$Sr${}_x$RuO${}_4$
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• A General Mechanism for Orbital Selective Phase Transitions
• Phase diagram of orbital-selective Mott transitions at finite temperatures
• Strong spin-phonon coupling unveiled by coherent phonon oscillations in Ca2RuO4
• Spin-orbit coupling induced Mott transition in Ca${}_{2-x}$Sr${}_x$RuO${}_4$ (0<x<0.2)
• Manifestations of Broken Symmetry: The Surface Phases of Ca(2-x)Sr(x)RuO4
• Anisotropic uniaxial pressure response of the Mott insulator Ca2RuO4
• Doping-driven Mott transition in La_{1-x}Sr_xTiO_3 via simultaneous electron and hole doping of t2g subbands
• Cooperative Effects of Strain and Electron Correlation in Epitaxial VO2 and NbO2
• Fock space embedding theory for strongly correlated topological phases
• Structural aspects of metamagnetism in Ca_{2-x}Sr_{x}RuO_4 (0.2 < x < 0.5): field tuning of orbital occupation
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• Orbital and spin correlations in Ca${}_{2-x}$Sr${}_x$RuO${}_4$: A mean field study
• Van Vleck excitons in Ca${}_2$RuO${}_4$
• Tuning of the Ru${}^{4+}$ ground-state orbital population in the $4{\mathbf{d}}^4$ Mott insulator Ca${}_2$RuO${}_4$ achieved by La doping
• Persistence of antiferromagnetic order upon La substitution in the $4d^4$ Mott insulator Ca${}_2$RuO${}_4$
• Can Orbital-Selective Néel Transitions Survive Strong Nonlocal Electronic Correlations?
• Abnormal $phase$ flip in coherent phonon oscillations of Ca${}_2$RuO${}_4$
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• A coherent phonon-induced hidden quadrupolar ordered state in Ca${}_2$RuO${}_4$
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• Hidden Phases Revealed at the Surface of Double-Layered Sr3(Ru1-xMnx)2O7
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• Orbital Selective Phase Transition
• The Iso-electronic Series $C{a}_{2-x}S{r}_{x}Ru{O}_4$: Structural Distortion, Effective Dimensionality, Spin Fluctuations and Quantum Criticality
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• Photoemission and Dynamical Mean Field Theory Study of Electronic Correlation in a $t_{2g}^5$ Metal of SrRhO${}_3$ Thin Film
• Interplay of metamagnetic and structural transitions in Ca${}_{2-x}$Sr${}_x$RuO${}_4$