t2g-orbital model on a honeycomb lattice: application to antiferromagnet SrRu2O6

TL;DR

This paper develops a minimal $t_{2g}$-orbital model on a honeycomb lattice to understand the antiferromagnetic properties of SrRu$_2$O$_6$, incorporating Coulomb interactions and spin-orbit coupling, predicting non-collinear magnetic moments.

Contribution

It introduces a novel $t_{2g}$-orbital model for SrRu$_2$O$_6$ that captures its antiferromagnetic order and predicts non-collinear magnetic moments due to strong spin-orbit coupling.

Findings

Antiferromagnetic order consistent with experiments

Non-collinear magnetic moments predicted

Model captures low energy band structure

Abstract

Motivated by the recent discovery of high temperature antiferromagnet SrRu$_2$O$_6$ and its potential to be the parent of a new superconductor, we construct a minimal $t_{2g}$-orbital model on a honeycomb lattice to simulate its low energy band structure. Local Coulomb interaction is taken into account through both random phase approximation and mean field theory. Experimentally observed Antiferromagnetic order is obtained in both approximations. In addition, our theory predicts that the magnetic moments on three $t_{2g}$-orbitals are non-collinear as a result of the strong spin-orbit coupling of Ru atoms.