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 $\left(xy\right)$ 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 $\left(U\right)$ and Hund's coupling $\left(J_H\right)$ in ${\mathrm{Li}}_2{\mathrm{RuO}}_3$.

• Received 11 December 2014
• Revised 20 January 2015

DOI:https://doi.org/10.1103/PhysRevB.91.115138