Electronic structure ofLi2RuO3studied by LDA and LDA+DMFT calculations and soft x-ray spectroscopy

Abstract

The electronic structure of ${\mathrm{Li}}_{2}{\mathrm{RuO}}_{3}$ was investigated using x-ray emission and absorption spectroscopy and by theoretical calculations employing two approaches: the local density approximation (LDA) and a combination of LDA with the cluster extension of dynamical mean-field theory (LDA+DMFT). The evolution of the spectral properties with the strength of electronic correlations is analyzed. We show that for moderate values of on-site Coulomb repulsion $U$ and intra-atomic Hund's rule exchange ${J}_{H},{\mathrm{Li}}_{2}{\mathrm{RuO}}_{3}$ is in an orbital-selective strongly correlated state in the sense that a part of the ${t}_{2g}$ manifold (i.e., $xz/yz)$ behaves as local atomic orbitals susceptible to Hubbard correlations, while the remaining $(xy)$ orbitals must be described as bond-centered molecular orbitals. Both theoretical approaches succeed in explaining the x-ray data, and a comparison of the theoretical and experimental spectra provides a reasonable estimate of the possible correlation strength $(U)$ and Hund's coupling $({J}_{H})$ in ${\mathrm{Li}}_{2}{\mathrm{RuO}}_{3}$.