Orbital disorder induced by charge fluctuations in vanadium spinels

Abstract

Motivated by recent experiments on vanadium spinels, $A$V${}_2$O${}_4$, that show an increasing degree of electronic delocalization for smaller cation sizes, we study the evolution of orbital ordering (OO) between the strong and intermediate-coupling regimes of a multi-orbital Hubbard Hamiltonian. The underlying magnetic ordering of the Mott insulating state leads to a rapid suppression of OO due to enhanced charge fluctuations along ferromagnetic bonds. Orbital double-occupancy is rather low at the transition point indicating that the system is in the crossover region between strong and intermediate-coupling regimes when the orbital degrees of freedom become disordered.

References in corpus (14)

• Colossal Magnetoresistant Materials: The Key Role of Phase Separation
• Structural, orbital, and magnetic order in vanadium spinels
• Orbital and spin chains in ZnV2O4
• Magnetic transition and orbital degrees of freedom in vanadium spinels
• Spin and Orbital Order of the Vanadium Spinel MgV2O4
• Orbital order in ZnV${}_2$O${}_4$
• Dimerization versus Orbital Moment Ordering in the Mott insulator YVO${}_3$
• CdV2O4: A rare example of a collinear multiferroic spinel
• Enhanced Pressure Dependence of Magnetic Exchange in A2+[V2]O4 Spinels Approaching the Itinerant Electron Limit
• Orbital order in vanadium spinels
• Homopolar bond formation in ZnV${}_2$O${}_4$ close to a metal-insulator transition
• Spin superstructure and noncoplanar ordering in metallic pyrochlore magnets with degenerate orbitals
• Large-J approach to strongly coupled spin-orbital systems
• Magnetic excitations in vanadium spinels

Cited by in corpus (5)

• Magnetic Field Induced Transition in Vanadium Spinels
• Phonon dispersion, Raman spectra and evidence for spin-phonon coupling in MnV${}_2$O${}_4$ from first-principles
• Transverse acoustic phonon anomalies at intermediate wavevectors in MgV${}_2$O${}_4$
• Limitations of unconstrained LSDA+$U$ calculations in predicting the electronic and magnetic ground state of a geometrically frustrated ZnV${}_2$O${}_4$ compound
• Electron quasi-itinerancy intertwined with quantum order by disorder in pyrochlore iridate magnetism