High-resolution resonant inelastic X-ray scattering (RIXS) at the oxygen K-edge has been used to study the orbital excitations of Ca2RuO4 and Sr2RuO4. In combination with linear dichroism X-ray absorption spectroscopy, the ruthenium 4d-orbital occupation and excitations were probed through their hybridization with the oxygen p-orbitals. These results are described within a minimal model, taking into account crystal field splitting and a spin-orbit coupling \lambda_{so}=200~meV. The effects of spin-orbit interaction on the electronic structure and implications for the Mott and superconducting ground states of (Ca,Sr)2RuO4 are discussed.
@article{arxiv.1503.01574,
title = {Spin-Orbit-Induced Orbital Excitations in Sr2RuO4 and Ca2RuO4: A Resonant Inelastic X-ray Scattering Study},
author = {C. G. Fatuzzo and M. Dantz and S. Fatale and P. Olalde-Velasco and N. E. Shaik and B. Dalla Piazza and S. Toth and J. Pelliciari and R. Fittipaldi and A. Vecchione and N. Kikugawa and J. S. Brooks and H. M. Rønnow and M. Grioni and Ch. Rüegg and T. Schmitt and J. Chang},
journal= {arXiv preprint arXiv:1503.01574},
year = {2015}
}