We show that the t2g2 perovskite LaVO3, 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 YVO3 and t2g1 titanates. In all these materials the crystal-field is sufficiently large to suppress the Kugel-Khomskii phase transition.
@article{arxiv.2209.04912,
title = {LaVO$_3$: a true Kugel-Khomskii system},
author = {Xue-Jing Zhang and Erik Koch and Eva Pavarini},
journal= {arXiv preprint arXiv:2209.04912},
year = {2022}
}