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 ${\mathrm{NdNiO}}_2$ and ${\mathrm{LaNiO}}_2$ using the combination of local density approximation and dynamical mean-field theory ($\mathrm{LDA}+\mathrm{DMFT}$). Adjusting a charge-transfer energy to match the experimental spectra, we determine the optimal model parameters and discuss the nature of the ${\mathrm{NdNiO}}_2$ 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 ${\mathrm{NdNiO}}_2$. The present Ni $L_3$ XAS and RIXS calculation for ${\mathrm{LaNiO}}_2$ cannot explain the difference from ${\mathrm{NdNiO}}_2$ spectra.

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无限层镍酸盐的核心级X射线光谱：LDA+DMFT研究

受最近对新发现的超导无限层镍酸盐的核心级 X 射线光发射光谱、X 射线吸收光谱 (XAS) 和共振非弹性 X 射线散射 (RIXS) 实验的启发，我们研究了核心级光谱母体化合物 ${\mathrm{氧化钕}}_2$ 和 ${\mathrm{氧化镧}}_2$ 使用局部密度近似和动态平均场理论的结合（$\mathrm{LDA}+\mathrm{DMFT}$）。调整电荷转移能量以匹配实验光谱，我们确定最佳模型参数并讨论${\mathrm{氧化钕}}_2$基态。我们发现 Nd 的自掺杂$5d$ 费米能量附近的状态禁止打开莫特-哈伯德间隙 ${\mathrm{氧化钕}}_2$. 现在的倪${升}_3$ XAS 和 RIXS 计算 ${\mathrm{氧化镧}}_2$ 无法解释与 ${\mathrm{氧化钕}}_2$ 光谱。