Saturation and self-absorption effects in the angle-dependent 2p3d resonant inelastic X-ray scattering spectra of Co³

Angle-dependent 2p3d resonant inelastic X-ray scattering spectra of a LaCoO₃ single crystal and a 55 nm LaCoO₃ film on a SrTiO₃ substrate are presented. Theoretical calculation shows that, with ∼20 meV resolved Co 2p3d resonant inelastic X-ray scattering (RIXS), the excited states of the isotropic ¹A_1g(O_h) ground state are split by 3d spin-orbit coupling, which can be distinguished via their angular dependence. However, strong self-absorption and saturation effects distort the spectra of the LaCoO₃ single crystal and limit the observation of small angular dependence. In contrast, the RIXS on 55 nm LaCoO₃ shows less self-absorption effects and preserves the angular dependence of the excited states.