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arXiv · 0808.3585

On the mechanism for orbital-ordering in KCuF3

E. Pavarini·E. Koch·A. I. Lichtenstein
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Abstract

The Mott insulating perovskite KCuF3 is considered the archetype of an orbitally-ordered system. By using the LDA+dynamical mean-field theory (DMFT) method, we investigate the mechanism for orbital-ordering (OO) in this material. We show that the purely electronic Kugel-Khomskii super-exchange mechanism (KK) alone leads to a remarkably large transition temperature of T_KK about 350 K. However, orbital-order is experimentally believed to persist to at least 800 K. Thus Jahn-Teller distortions are essential for stabilizing orbital-order at such high temperatures.

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E. Pavarini, E. Koch, A. I. Lichtenstein. 2008-08-26. On the mechanism for orbital-ordering in KCuF3. https://doi.org/10.1103/physrevlett.101.266405

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