Quantum Versus Jahn-Teller Orbital Physics in YVO 3 and LaVO 3
Abstract
We argue that the large Jahn-Teller (JT) distortions in YVO
3
and LaVO
3
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 YVO
3
in C-type antiferromagnetic state is attributed to the inequivalent VO
2
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 LaVO
3
, although it is weak.