One-dimensional orbital fluctuations and the exotic magnetic properties of YVO${}_3$

Abstract

Starting from the Mott insulator picture for cubic vanadates, we derive and investigate the model of superexchange interactions between V${}^{3+}$ ions, with nearly degenerate $t_{2g}$ orbitals occupied by two electrons each. The superexchange interactions are strongly frustrated and demonstrate a strong interrelation between possible types of magnetic and orbital order. We elucidate the prominent role played by fluctuations of $yz$ and $xz$ orbitals which generate ferromagnetic superexchange interactions even in the absence of Hund's exchange. In this limit we find orbital valence bond state which is replaced either by $C$-type antiferromagnetic order with weak $G$-type orbital order at increasing Hund's exchange, or instead by $G$-type antiferromagnetic order when the lattice distortions stabilize $C$-type orbital order. Both phases are observed in YVO${}_3$ and we argue that a dimerized $C$-type antiferromagnetic phase with stronger and weaker FM bonds alternating along the c axis may be stabilized by large spin-orbital entropy at finite temperature. This suggests a scenario which explains the origin of the exotic $C$-AF order observed in YVO${}_3$ in the regime of intermediate temperatures and allows one to specify the necessary ingredients of a more complete future theory.

23 pages, 15 figures

References in corpus (5)

• Spin-Orbital Entanglement and Violation of the Goodenough-Kanamori Rules
• Neutron diffraction study of YVO3, NdVO3, and TbVO3
• Lattice Distortion and Magnetism of 3d-$t_{2g}$ Perovskite Oxides
• Theory of optical spectral weights in Mott insulators with orbital degrees of freedom
• Entropy Driven Dimerization in a One-Dimensional Spin-Orbital Model

Cited by in corpus (13)

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• Fingerprints of spin-orbital entanglement in transition metal oxides
• Evolution of Spin-Orbital-Lattice Coupling in the $R$VO${}_3$ Perovskites
• Frustration and entanglement in the $t_{2g}$ spin--orbital model on a triangular lattice: valence--bond and generalized liquid states
• Spin-orbital resonating valence bond liquid on a triangular lattice: Evidence from finite-cluster diagonalization
• Spin, orbital ordering and magnetic dynamics of LaVO3: magnetization, heat capacity and neutron scattering studies
• Quantum phase transitions in exactly solvable one-dimensional compass models
• Defect states and spin-orbital physics in doped vanadates Y1-xCaxVO3
• Imprinted atomic displacements drive spin-orbital order in a vanadate perovskite
• A Colossal Electroresistance response, accompanied by metal-insulator transition, in a mixed-valent vanadate
• Low-energy V t2g orbital excitations in NdVO3
• Exact deconfined gauge structures in the higher-spin Yao-Lee model: a quantum spin-orbital liquid with spin fractionalization and non-Abelian anyons
• Orbital Rotations induced by Charges of Polarons and Defects in Doped Vanadates