Orbital and spill orderings in YVO3 and LaVO3 in the generalized gradient approximation

The orbital and spin orderings of d(2) Jahn-Teller systems are studied in the generalized gradient approximation (GGA) by using the full-potential linearized augmented-plane-wave method. For the low temperature distorted crystal structures in YVO3 and LaVO3 perovskites, we show that orbital orderings and insulating band structures are obtained properly in GGA, but are not in the local spin density approximation. Bond length alternation in the ab plane cause the C-type and G-type orderings of d(yz) and d(zx) orbitals, which in turn stabilize theG-type and C-type antiferromagnetic spin orderings in YVO3 and LaVO3, respectively. The total energy calculation partially confirms the relation between orbital and spin orderings, and indicates that the extent of the orbital ordering is still insufficient for YVO3 in GGA.