Extended Data Fig. 2: Ni L-edge, La M4-edge and Nd M5-edge x-ray absorption spectra (XAS).
From: Electronic structure of the parent compound of superconducting infinite-layer nickelates
a, XAS of LaNiO3 and LaNiO2 across the Ni L3,2-edge before subtraction of the La M4 absorption peak. The XAS of NiO powder is also shown. Spectra are offset in vertical direction for clarity. b, XAS of NdNiO3 and NdNiO2 across the Nd M5-edge. The XAS were taken using total fluorescence yield. The XAS spectra across the rare-earth M-edges of the La- and Nd-based infinite-layer nickelates are essentially identical to those of their perovskite counterparts (LaNiO3 and NdNiO3). This implies a similar configuration of 4f states for both types of nickelates and that the 4f states of La3+ and Nd3+ do not hybridize in any significant way with the Ni 3d states.
