Ab initio study on the possible magnetic topological semimetallic state in MnMg$_{2}$O$_{4}$}

TL;DR

This study uses first-principles calculations to explore the electronic and magnetic properties of MnMg₂O₄, revealing its potential as a magnetic topological semimetal with significant anomalous Hall conductivity.

Contribution

It provides the first ab initio analysis of MnMg₂O₄'s electronic structure, magnetic state, and topological features, highlighting its semimetallic and anomalous Hall effects.

Findings

MnMg₂O₄ is a half-metallic semimetal with line nodes.

The anomalous Hall conductivity peaks at 200 S/cm near the Fermi level.

The material exhibits a high-spin state with a 3 eV minority spin gap.

Abstract

We study the electronic state of an inverse spinel compound MnMg$_{2}$O$_{4}$ based on first-principles calculations. The high-spin state is realized in Mn ions on the diamond lattice, resulting in that this material is found to be a half-metallic semimetal with the minority spin-gap about 3eV, and also with line nodes in the Brillouin zone. The intrinsic anomalous Hall conductivity (AHC) is also computed as a function of the chemical potential of the system assuming the rigid band structure, and is found to exhibit a peak structure with a maximum value of 200 S/cm at only 15 meV above the Fermi level. The relation between the large AHC and Berry curvature in the Brillouin zone is also discussed.