We argue that the large Jahn-Teller (JT) distortions in YVO3 and LaVO3 should suppress the quantum orbital fluctuation. The unusual magnetic properties can be well explained based on LDA+U calculations using experimental structures, in terms of the JT orbital. The observed splitting of the spin-wave dispersions for YVO3 in C-type antiferromagnetic state is attributed to the inequivalent VO2 layers in the crystal structure, instead of the ``orbital Peierls state''. Alternative stacking of ab-plane exchange couplings produces the c-axis spin-wave splitting, thus the spin system is highly three dimensional rather than quasi-one-dimensional. Similar splitting is also predicted for LaVO3, although it is weak.
@article{arxiv.cond-mat/0409299,
title = {Quantum Versus Jahn-Teller Orbital Physics in YVO$_3$ and LaVO$_3$},
author = {Zhong Fang and Naoto Nagaosa},
journal= {arXiv preprint arXiv:cond-mat/0409299},
year = {2009}
}