Core-Level X-Ray Spectroscopy of Infinite-Layer Nickelate: LDA + DMFT Study

Motivated by recent core-level x-ray photoemission spectroscopy, x-ray absorption spectroscopy (XAS), and resonant inelastic x-ray scattering (RIXS) experiments for the newly discovered superconducting infinite-layer nickelate, we investigate the core-level spectra of the parent compoundsNdNiO2andLaNiO2using the combination of local density approximation and dynamical mean-field theory (LDA+DMFT). Adjusting a charge-transfer energy to match the experimental spectra, we determine the optimal model parameters and discuss the nature of theNdNiO2ground state. We find that self-doping from the Nd5dstates in the vicinity of the Fermi energy prohibits opening of a Mott-Hubbard gap inNdNiO2. The present NiL3XAS and RIXS calculation forLaNiO2cannot explain the difference fromNdNiO2spectra.