Orbital Physics in the Perovskite Ti Oxides

Abstract

In the perovskite Ti oxide RTiO3 (R=rare-earth ions), the Ti t2g orbitals and spins in the 3d^1 state couple each other through the strong electron correlations, resulting in a rich variety of orbital-spin phases. The origin and nature of orbital-spin states of these Mott insulators have been intensively studied. In this article, we review the studies on orbital physics in the perovskite titanates. We focus on the following three topics: (1) the origin and nature of the ferromagnetism as well as the orbital ordering in the compounds with relatively small R ions such as GdTiO3 and YTiO3, (2) the origin of the G-type antiferromagnetism and the orbital state in LaTiO3, and (3) the orbital-spin structures in other AFM(G) compounds with relatively large R ions (R=Ce, Pr, Nd and Sm). On the basis of these discussions, we discuss the whole phase diagram together with mechanisms of the magnetic phase transition. We also show that the Ti t2g degeneracy is inherently lifted in the titanates, which allows the single-band descriptions of the ground-state and low-energy electronic structures as a good starting point. Our analyses indicate that these compounds offer touchstone materials described by the single-band Hubbard model on the cubic lattice. From this insight, we also reanalyze the hole-doped titanates. Experimentally revealed filling-dependent and bandwidth-dependent properties and the critical behavior of the metal-insulator transitions are discussed in the light of theories based on the single-band Hubbard models.

Review article, 26 pages, to appear in New Journal of Physics

References in corpus (3)

• Orbital-Spin Structure and Coupling to Lattice in RTiO${}_3$ with R=La,Pr,Nd and Sm
• G-type antiferromagnetism and orbital ordering due to the crystal field from the rare-earth ions induced by the GdFeO_3-type distortion in RTiO_3 with R=La, Pr, Nd and Sm
• Precise Determination of Phase Diagram for Two-Dimensional Hubbard Model with Filling- and Bandwidth-Control Mott Transitions: Grand-Canonical Path-Integral Renormalization Group Approach

Cited by in corpus (35)

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• Optical Stabilization of Fluctuating High Temperature Ferromagnetism in YTiO${}_3$
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• Combining DFT and Many-Body Methods to Understand Correlated Materials
• Evolution of Spin-Orbital-Lattice Coupling in the $R$VO${}_3$ Perovskites
• Crystal-field splitting for low symmetry systems in ab initio calculations
• Macroscopic quantum dynamics of pi-junctions with ferromagnetic insulators
• Optical response of ferromagnetic YTiO_3 studied by spectral ellipsometry
• Charge transfer and hybrid ferroelectricity in (YFeO${}_3$)${}_n$/(YTiO${}_3$)${}_n$ magnetic superlattices
• Origin of the orbital and spin orderings in rare-earth titanates
• Ferromagnetism and Lattice Distortions in the Perovskite YTiO${}_3$
• Phase separation in doped Mott insulators
• Structural and metal-insulator transitions in rhenium based double perovskites via orbital ordering
• Dipole-active optical phonons in YTiO_3: ellipsometry study and lattice-dynamics calculations
• Strain-engineered A-type antiferromagnetic order in YTiO${}_3$: a first-principles calculation
• Uniaxial strain control of bulk ferromagnetism in rare-earth titanates
• Ferroelectric control of spin-polarized two-dimensional electron gas
• Nature of the ferromagnetic-antiferromagnetic transition in Y${}_{1-x}$La${}_x$TiO${}_3$
• Strain-tunable metamagnetic critical endpoint in Mott insulating rare-earth titanates
• Magneto-Elastic Coupling to Coherent Acoustic Phonon Modes in Ferrimagnetic Insulator GdTiO${}_3$
• Response of the lattice across the filling-controlled Mott metal-insulator transition of a rare earth titanate
• Charge transfer model for the electronic structure of layered ruthenates
• Two-component electronic phase separation in the doped Mott insulator Y${}_{1-x}$Ca${}_x$TiO${}_3$
• Growth and characterization of large (Y,La)TiO${}_3$ and (Y,Ca)TiO${}_3$ single crystals
• Magnetism and electronic structure of ($001$)- and ($111$)-oriented LaTiO${}_3$ bilayers sandwiched in LaScO${}_3$ barriers
• Strain driven sequential magnetic transitions in strained GdTiO3 on compressive substrates: a first-principles study
• Muon spin relaxation study of LaTiO3 and YTiO3
• Dynamics of photo-induced ferromagnetism in oxides with orbital degeneracy
• Orientation-dependent magnetism and orbital structure of strained YTiO${}_3$ films on LaAlO${}_3$ substrates
• Orthorhombic distortion drives orbital ordering in an antiferromagnetic 3$d^1$ Mott insulator
• Tetrahedral rotations in alkaline-earth metal orthovanadates
• Magnetic resonance study of rare-earth titanates
• Effect of random antiferromagnetic exchange on the spin waves in a three-dimensional Heisenberg ferromagnet