Electronic structure of Li sub(2) RuO sub(3) studied by LDA and LDA+DMFT calculations and soft x-ray spectroscopy

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2015-03, Vol.91 (11)
• Main Authors: Pchelkina, Z V, Pitman, A L, Moewes, A, Kurmaev, E Z, Tan, Teck-Yee, Peets, D C, Park, Je-Geun, Streltsov, S V
• Format: Article
• Language: English
• Subjects: Condensed matter; Correlation; Electronic structure; Mathematical analysis; Orbitals; Spectra; Strength; X-rays
• ISSN: 1098-0121; 1550-235X

The electronic structure of Li sub(2) RuO sub(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 sub(H), Li sub(2) RuO sub(3) is in an orbital-selective strongly correlated state in the sense that a part of the t sub(2)g 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 sub(H)) in Li sub(2) RuO sub(3).