Abstract
We have investigated the excitation spectra of Mott insulator . Taking into account a relativistic multiplet structure of Ir ions, we have calculated the optical conductivity and resonant inelastic x-ray scattering (RIXS) spectra, which manifest different features from those of a canonical system . Distinctly from the two-peak structure in , in has a broad single peak dominated by interband transitions from to . RIXS spectra exhibit the spin-orbit (SO) exciton that has a two-peak structure arising from the crystal-field effect, and the magnon peak at energies much lower than in . In addition, a small peak near the optical-absorption edge is found in RIXS spectra, originating from the coupling between the electron-hole (-) excitation and the SO exciton. Our findings corroborate the validity of the relativistic electronic structure and importance of both itinerant and local features in .
- Received 1 July 2013
- Revised 19 October 2013
DOI:https://doi.org/10.1103/PhysRevB.89.081109
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