Metallic ruthenium ilmenites: first-principles study of MgRuO$_3$ and CdRuO$_3$

Seong-Hoon Jang; Yukitoshi Motome

doi:10.1063/5.0185801

paper

Metallic ruthenium ilmenites: first-principles study of MgRuO $_{3}$ and CdRuO $_{3}$

arXiv:2306.11542 · doi:10.1063/5.0185801

Abstract

Ilmenites $A B$ O $_{3}$ provide a platform for electron correlation and magnetism on alternatively stacked honeycomb layers of edge-sharing $A$ O $_{6}$ or $B$ O $_{6}$ octahedra. When $A$ and $B$ are $3 d$ transition metals, strong electron correlation makes the systems Mott insulators showing various magnetic properties, while when $B$ is Ir with $5 d$ electrons, competition between electron correlation and spin-orbit coupling realizes a spin-orbital coupled Mott insulator as a potential candidate for quantum spin liquids. Here we theoretically investigate intermediate $4 d$ ilmenites, $A$ RuO $_{3}$ with $A$ =Mg and Cd, which were recently synthesized and shown to be metallic, unlike the $3 d$ and $5 d$ cases. By using first-principles calculations, we optimize the lattice structures and obtain the electronic band structures. We show that MgRuO $_{3}$ exhibits strong dimerization on RuO $_{6}$ honeycomb layers, leading to the formation of bonding and anti-bonding bands for one of three $t_{2 g}$ orbitals; the lattice symmetry is lowered from $R 3 ˉ$ to $P 1 ˉ$ , and the Fermi surfaces are composed of the other two $t_{2 g}$ orbitals. In contrast, we find that CdRuO $_{3}$ has a lattice structure close to $R 3 ˉ$ , and all three $t_{2 g}$ orbitals contribute almost equally to the Fermi surfaces. Comparison of our results with other Ru honeycomb materials such as Li $_{2}$ RuO $_{3}$ indicates that the metallic ruthenium ilmenites stand on a subtle balance among electron correlation, spin-orbit coupling, and electron-phonon coupling.

Metallic ruthenium ilmenites: first-principles study of MgRuO3​ and CdRuO3​

Abstract

References in corpus (8)

Metallic ruthenium ilmenites: first-principles study of MgRuO $_{3}$ and CdRuO $_{3}$