Core-Level X-Ray Spectroscopy of Infinite-Layer Nickelate: <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>LDA</mml:mi><mml:mo>+</mml:mo><mml:mi>DMFT</mml:mi></mml:mrow></mml:math> Study
Keisuke Higashi, Mathias Winder, Jan Kuneš, Atsushi Hariki
Abstract
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 compounds NdNiO 2 and LaNiO 2 using 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 the NdNiO 2 ground state. We find that self-doping from the Nd 5d states in the vicinity of the Fermi energy prohibits opening of a Mott-Hubbard gap in NdNiO 2 . The present Ni L 3 XAS and RIXS calculation for LaNiO 2 cannot explain the difference from NdNiO 2 spectra.