A hybrid-exchange density-functional theory study of the electronic structure of $\mathrm{MnV}_2\mathrm{O}_4$: Exotic orbital ordering in the cubic structure

TL;DR

This study uses hybrid-exchange density functional theory to investigate the electronic structures of cubic and tetragonal MnV₂O₄, revealing exotic orbital ordering and magnetic properties consistent with experimental and previous theoretical results.

Contribution

It provides new insights into the orbital ordering in MnV₂O₄, especially the exotic ferro- and anti-ferro orbital orderings in the cubic phase, using advanced computational methods.

Findings

Tetragonal phase exhibits anti-ferro orbital ordering on V sites.

Cubic phase shows exotic orbital ordering with ferro- and anti-ferro patterns.

Results align well with previous theoretical and experimental data.

Abstract

The electronic structures of the cubic and tetragonal $\mathrm{MnV}_2\mathrm{O}_4$ have been studied by using hybrid-exchange density functional theory. The computed electronic structure of the tetragonal phase shows an anti-ferro orbital ordering on V sites and a ferrimagnetic ground state (the spins on V and Mn are anti-aligned). These results are in a good agreement with the previous theoretical result obtained from the local-density approximation+$U$ methods [S. Sarkar, et. al., Phys. Rev. Lett. 102, 216405 (2009)]. Moreover, the electronic structure, especially the projected density of states of the cubic phase has been predicted with a good agreement with the recent soft x-ray spectroscopy experiment. Similar to the tetragonal phase, the spins on V and Mn in the cubic structure favour a ferrimagnetic configuration. Most interesting is that the computed charge densities of the spin-carrying orbitals on V in the cubic phase show an exotic orbital ordering, i.e., a ferro-orbital ordering along [110] but an anti-ferro-orbital ordering along [$\overline{1}$10].