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arXiv · 2209.04912

LaVO$_3$: a true Kugel-Khomskii system

Xue-Jing Zhang·Erik Koch·Eva Pavarini
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Abstract

We show that the $t_{2g}^2$ perovskite LaVO$_3$, in its orthorhombic phase, is a rare case of a system hosting an orbital-ordering Kugel-Khomskii phase transition, rather than being controlled by the Coulomb-enhanced crystal-field splitting. We find that, as a consequence of this, the magnetic transition is close to (and even above) the super-exchange driven orbital-ordering transition, whereas typically magnetism arises at much lower temperatures than orbital ordering. Our results support the experimental scenario of orbital-ordering and G-type spin correlations just above the monoclinic-to-orthorhombic structural change. To explore the effects of crystal-field splitting and filling, we compare to YVO$_3$ and $t_{2g}^1$ titanates. In all these materials the crystal-field is sufficiently large to suppress the Kugel-Khomskii phase transition.

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Xue-Jing Zhang, Erik Koch, Eva Pavarini. 2022-09-11. LaVO$_3$: a true Kugel-Khomskii system. https://doi.org/10.1103/physrevb.106.115110

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