Electronic structure and resonant inelastic x-ray scattering in osmates. II. Pyrochlore Cd2Os2O7

Abstract

We have investigated the electronic and magnetic properties of the pyrochlore osmate ${\mathrm{Cd}}_{2}{\mathrm{Os}}_{2}{\mathrm{O}}_{7}$ within density functional theory using the generalized gradient approximation with taking into account strong Coulomb correlations in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. ${\mathrm{Cd}}_{2}{\mathrm{Os}}_{2}{\mathrm{O}}_{7}$ is a Mott insulator with all-in-all-out magnetic order. The optical spectra, x-ray absorption spectra, and x-ray magnetic circular dichroism at the Os ${L}_{2,3}$ edges in the pyrochlore osmate ${\mathrm{Cd}}_{2}{\mathrm{Os}}_{2}{\mathrm{O}}_{7}$ have been investigated theoretically from first principles. The calculated results are in good agreement with experimental data. We have also investigated theoretically the resonant inelastic x-ray scattering (RIXS) spectrum at the Os ${L}_{3}$ edge. The experimentally measured RIXS spectrum of ${\mathrm{Cd}}_{2}{\mathrm{Os}}_{2}{\mathrm{O}}_{7}$ in addition to the elastic scattering peak at 0 eV possesses a sharp feature at 0.9 eV corresponding to transitions within the Os ${t}_{2g}$ levels, a strong intense peak at around 4.5 eV which is from ${t}_{2g}\ensuremath{\rightarrow}{e}_{g}$ transitions, and a wide structure stretching from 5.5 eV to 15 eV that corresponds to ligand-to-metal charge transfer excitations.