The discovery of unconventional superconductivity in hole doped NdNiO₂, similar to CaCuO₂, has received enormous attention. However, different from CaCuO₂, RNiO₂ (R = Nd, La) has itinerant electrons in the rare-earth spacer layer. Previous studies show that the hybridization between Ni-\({d}_{{x}^{2}-{y}^{2}}\) and rare-earth-d orbitals is very weak and thus RNiO₂ is still a promising analog of CaCuO₂. Here, we perform first-principles calculations to show that the hybridization between Ni-\({d}_{{x}^{2}-{y}^{2}}\) orbital and itinerant electrons in RNiO₂ is substantially stronger than previously thought. The dominant hybridization comes from an interstitial-s orbital rather than rare-earth-d orbitals, due to a large inter-cell hopping. Because of the hybridization, Ni local moment is screened by itinerant electrons and the critical U_Ni for long-range magnetic ordering is increased. Our work shows that the electronic structure of RNiO₂ is distinct from CaCuO₂, implying that the observed superconductivity in infinite-layer nickelates does not emerge from a doped Mott insulator.

类似于CaCuO _2的空穴掺杂NdNiO ₂中非常规超导性的发现受到了极大的关注。但是，与CaCuO ₂不同，R NiO ₂（R  ＝ Nd，La）在稀土间隔层中具有流动电子。以前的研究表明，Ni基之间的杂交\（{d} _ {{X} ^ {2} - {Y} ^ {2}} \）和稀土的地基d轨道是非常弱的，因此ř的NiO ₂是仍然是有希望的CaCuO ₂类似物。在这里，我们执行第一性原理计算，以显示Ni- \（{d} _ {{x} ^ {2}-{y} ^ {2}} \）之间的杂交R NiO _2中的轨道和流动电子比以前认为的要强得多。占主导地位的杂交来自一个interstitial-小号轨道，而不是稀土的地基d轨道，由于大型小区间跳跃。由于发生了杂化，镍的局部矩被流动电子屏蔽，并且增加了用于长距离磁排序的临界U _Ni。我们的工作表明，R NiO ₂的电子结构不同于CaCuO ₂，这意味着在无限层镍酸盐中观察到的超导性不会从掺杂的Mott绝缘体中出现。