Theory for spin and orbital orderings in high temperature phase in $YVO_3$

TL;DR

This paper develops a microscopic model to explain the sequence of orbital and spin orderings observed in high-temperature phases of YVO3, aligning well with recent neutron diffraction experiments.

Contribution

It introduces a mean field classical solution for the spin-orbital superexchange model specific to YVO3, predicting orbital and spin orderings consistent with experimental data.

Findings

Predicts antiferro-orbital ordering at higher temperature (~200K)

Predicts C-type antiferromagnetic spin ordering at lower temperature (~114K)

Qualitatively matches observed phase transitions in YVO3

Abstract

Motivated by the recent neutron diffraction experiment on $YVO_3$, we consider a microscopic model where each $V^{3+}$ ion is occupied by two 3d electrons of parallel spins with two fold degenerate orbital configurations. The mean field classical solutions of the spin-orbital superexchange model predicts an antiferro-orbital ordering at a higher temperature followed by a C-type antiferromagnetic spin ordering at a lower temperature. Our results are qualitatively consistent with the observed orbital phase transition at $\sim 200K$ and the spin phase transition at $\sim 114K$ in $YVO_3$.