Orbital ordering in frustrated Jahn-Teller systems with 90 degrees exchange

M.V. Mostovoy; D.I Khomskii

doi:10.1103/physrevlett.89.227203

Orbital ordering in frustrated Jahn-Teller systems with 90 degrees exchange

M.V. Mostovoy, D.I Khomskii

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Abstract

We show that superexchange interactions in frustrated Jahn-Teller systems with transition metal ions connected by the 90° metal-oxygen-metal bonds (e.g., NaNiO2, LiNiO2, and ZnMn2O4) are much different from those in materials with the 180° bonds. In the 90°-exchange systems spins and orbitals are decoupled: the spin exchange is much weaker than the orbital one and it is ferromagnetic for all orbital states. Though the mean-field orbital ground state is strongly degenerate, quantum orbital fluctuations select particular ferro-orbital states. We explain the orbital and magnetic ordering observed in NaNiO2 and show that LiNiO2 is not a spin-orbital liquid.

Original language	English
Article number	227203
Number of pages	4
Journal	Physical Review Letters
Volume	89
Issue number	22
DOIs	https://doi.org/10.1103/physrevlett.89.227203
Publication status	Published - 2002

Keywords

TRANSITION-METAL OXIDES
HEISENBERG-ANTIFERROMAGNET
DISORDER
LINIO2
SPECTRA
PHYSICS
ORIGIN
LIQUID
LATIO3

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title = "Orbital ordering in frustrated Jahn-Teller systems with 90 degrees exchange",

abstract = "We show that superexchange interactions in frustrated Jahn-Teller systems with transition metal ions connected by the 90° metal-oxygen-metal bonds (e.g., NaNiO2, LiNiO2, and ZnMn2O4) are much different from those in materials with the 180° bonds. In the 90°-exchange systems spins and orbitals are decoupled: the spin exchange is much weaker than the orbital one and it is ferromagnetic for all orbital states. Though the mean-field orbital ground state is strongly degenerate, quantum orbital fluctuations select particular ferro-orbital states. We explain the orbital and magnetic ordering observed in NaNiO2 and show that LiNiO2 is not a spin-orbital liquid.",

keywords = "TRANSITION-METAL OXIDES, HEISENBERG-ANTIFERROMAGNET, DISORDER, LINIO2, SPECTRA, PHYSICS, ORIGIN, LIQUID, LATIO3",

author = "M.V. Mostovoy and D.I Khomskii",

note = "Relation: http://www.rug.nl/natuurkunde/ date_submitted:2007 Rights: University of Groningen. Materials Science Centre",

year = "2002",

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language = "English",

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journal = "Physical Review Letters",

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T1 - Orbital ordering in frustrated Jahn-Teller systems with 90 degrees exchange

AU - Mostovoy, M.V.

AU - Khomskii, D.I

N1 - Relation: http://www.rug.nl/natuurkunde/ date_submitted:2007 Rights: University of Groningen. Materials Science Centre

PY - 2002

Y1 - 2002

N2 - We show that superexchange interactions in frustrated Jahn-Teller systems with transition metal ions connected by the 90° metal-oxygen-metal bonds (e.g., NaNiO2, LiNiO2, and ZnMn2O4) are much different from those in materials with the 180° bonds. In the 90°-exchange systems spins and orbitals are decoupled: the spin exchange is much weaker than the orbital one and it is ferromagnetic for all orbital states. Though the mean-field orbital ground state is strongly degenerate, quantum orbital fluctuations select particular ferro-orbital states. We explain the orbital and magnetic ordering observed in NaNiO2 and show that LiNiO2 is not a spin-orbital liquid.

AB - We show that superexchange interactions in frustrated Jahn-Teller systems with transition metal ions connected by the 90° metal-oxygen-metal bonds (e.g., NaNiO2, LiNiO2, and ZnMn2O4) are much different from those in materials with the 180° bonds. In the 90°-exchange systems spins and orbitals are decoupled: the spin exchange is much weaker than the orbital one and it is ferromagnetic for all orbital states. Though the mean-field orbital ground state is strongly degenerate, quantum orbital fluctuations select particular ferro-orbital states. We explain the orbital and magnetic ordering observed in NaNiO2 and show that LiNiO2 is not a spin-orbital liquid.

KW - TRANSITION-METAL OXIDES

KW - HEISENBERG-ANTIFERROMAGNET

KW - DISORDER

KW - LINIO2

KW - SPECTRA

KW - PHYSICS

KW - ORIGIN

KW - LIQUID

KW - LATIO3

U2 - 10.1103/physrevlett.89.227203

DO - 10.1103/physrevlett.89.227203

M3 - Article

VL - 89

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

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