Atomic spin, molecular orbitals, and anomalous antiferromagnetism in insulating V{sub 2}O{sub 3}
A theory of the orbital ordering and the anomalous antiferromagetism in V{sub 2}O{sub 3} is developed on the basis of a realistic description of the V{sup 3+} atomic states. The effective electronic degrees of freedom in the insulating phase are found to be successively reduced to a set of molecular orbitals of V pairs along the trigonal axis. We derive the molecular interactions for the lowest orbital doublet and analyze their possible ordered phases in analogy with the Kugel-Khomskii model for the cubic perovskites. It is shown that the complex spin structure of V{sub 2}O{sub 3} is stabilized uniquely in a reasonable parameter region, and that it is associated with an unusual ferro-type orbital order involving the intramolecular correlation of V atomic orbitals. This characteristic orbital state is shown to be consistent with the monoclinic lattice distortion, the anisotropy of spin exchange couplings, and the spin orientation in the antiferromagnetic phase of V{sub 2}O{sub 3}. Based on those analyses, improved molecular orbital states are proposed and recent experiments on neutron and x-ray scattering are discussed.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40205470
- Journal Information:
- Physical Review B, Vol. 63, Issue 14; Other Information: DOI: 10.1103/PhysRevB.63.144422; Othernumber: PRBMDO000063000014144422000001; 007114PRB; PBD: 1 Apr 2001; ISSN 0163-1829
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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