Orbital and spin orderings inYVO3andLaVO3in the generalized gradient approximation

Abstract

The orbital and spin orderings of ${\mathit{d}}^2$ 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 ${\mathrm{YVO}}_3$ and ${\mathrm{LaVO}}_3$ 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 alternations in the ab plane cause the C-type and G-type orderings of ${\mathit{d}}_{\mathit{yz}}$ and ${\mathit{d}}_{\mathit{zx}}$ orbitals, which in turn stabilize the G-type and C-type antiferromagnetic spin orderings in ${\mathrm{YVO}}_3$ and ${\mathrm{LaVO}}_3$, 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 ${\mathrm{YVO}}_3$ in GGA. © 1996 The American Physical Society.