Dimerization versus Orbital-Moment Ordering in a Mott Insulator
- 16 December 2003
- journal article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 91 (25), 257203
- https://doi.org/10.1103/physrevlett.91.257203
Abstract
We use exact diagonalization combined with mean-field theory to investigate the phase diagram of the spin-orbital model for cubic vanadates. The spin-orbit coupling competes with Hund's exchange and triggers a novel phase, with the ordering of $t_{2g}$ orbital magnetic moments stabilized by the tilting of VO$_6$ octahedra. It explains qualitatively spin canting and reduction of magnetization observed in YVO$_3$. At finite temperature an orbital Peierls instability in the $C$-type antiferromagnetic phase induces modulation of magnetic exchange constants even in absence of lattice distortions. The calculated spin structure factor shows a magnon splitting due to the orbital Peierls dimerization.Comment: 4 pages, 5 figures, Revte
Keywords
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