Electronic structure and resonant inelastic X-ray scattering in pyrochlore Y2Os2O7

We have investigated the electronic and magnetic properties of the pyrochlore osmate Y2Os2O7 within the density-functional theory using the generalized gradient approximation, taking into account strong Coulomb correlations in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. Y2Os2O7 is a Mott insulator with all-in/all-out magnetic order. The X-ray absorption spectra and X-ray magnetic circular dichroism at the Os edges have been investigated theoretically using first-principles calculations. We have also investigated the resonant inelastic X-ray scattering (RIXS) spectrum at the Os L3 edge. The calculated results are in good agreement with experimental data. The experimentally measured RIXS spectrum of Y2Os2O7, in addition to the elastic scattering peak at 0 eV, possesses a sharp feature at ≤ 2.0 eV corresponding to transitions within the Os t2g levels, an intense peak at around 4.5 eV, which is from t2g → eg transitions, and a wide structure stretching from 7 to 15 eV that corresponds to ligand-to-metal charge transfer excitations. We have also presented comprehensive theoretical calculations of the RIXS spectrum at the oxygen K edge.