Charge and orbital order in transition metal oxides

Oles, Andrzej M.

doi:10.48550/arxiv.1008.2515

Cited by 1 publication

(3 citation statements)

References 160 publications

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“…In obtaining a more compact form of the Hamiltonian (7), one has to put the expression for various projection operators in the expression. The final form of the spin-orbital Hamiltonian is shown in equation (11) with superexchange constants given by…”

Section: Discussion and Summarymentioning

confidence: 99%

“…The spin-orbital Hamiltonian (11) shows that the dynamics of the orbitals and spins degrees of freedom are coupled to one other. This implies orbital ordering must dictate low temperature spin ordering.…”

Section: A Computation Of Spin Exchange Couplingsmentioning

confidence: 99%

“…Further, the coupling of spin and lattice degrees of freedom can also be shown to have interesting consequences for spin ordering 9,10 . In this way, the presence of multiple couplings between various degrees of freedom leads generically to the separation of energy scales at which the ordering of the orbitals and spins takes place [11][12][13][14] . Equally importantly, such interactions also offer multiple ways by which the system can relieve any inherent frustration among the spins and attain the ordering of spins.…”

Section: Introductionmentioning

confidence: 99%

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Orbital and spin ordering physics of the Mn3O4 spinel

Pal

Lal

2017

Phys. Rev. B

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Motivated by recent experiments, we present a comprehensive theoretical study of the geometrically frustrated strongly correlated magnetic insulator Mn3O4 spinel oxide based on a microscopic Hamiltonian involving lattice, spin and orbital degrees of freedom. Possessing the physics of degenerate eg orbitals, this system shows a strong Jahn-Teller effect at high temperatures. Further, careful attention is paid to the special nature of the superexchange physics arising from the 90 o Mn-O-Mn bonding angle. The Jahn-Teller and superexchange-based orbital-spin Hamiltonians are then analysed in order to track the dynamics of orbital and spin ordering. We find that a high-temperature structural transition results in orbital ordering whose nature is mixed with respect to the two originally degenerate eg orbitals. This ordering of orbitals is shown to relieve the intrinsic geometric frustration of the spins on the spinel lattice, leading to ferrimagnetic Yafet-Kittel ordering at lowtemperatures. Finally, we develop a model for a magnetoelastic coupling in Mn3O4, enabling a systematic understanding of the experimentally observed complexity in the low-temperature structural and magnetic phenomenology of this spinel. Our analysis predicts that a quantum fluctuation-driven orbital-spin liquid phase may be stabilised at low temperatures upon the application of pressure.

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Section: Discussion and Summarymentioning

confidence: 99%

Section: A Computation Of Spin Exchange Couplingsmentioning

confidence: 99%