School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853.
Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853.
Proc Natl Acad Sci U S A. 2021 Jan 12;118(2). doi: 10.1073/pnas.2007683118.
The recent observation of superconductivity in [Formula: see text] has raised fundamental questions about the hierarchy of the underlying electronic structure. Calculations suggest that this system falls in the Mott-Hubbard regime, rather than the charge-transfer configuration of other nickel oxides and the superconducting cuprates. Here, we use state-of-the-art, locally resolved electron energy-loss spectroscopy to directly probe the Mott-Hubbard character of [Formula: see text] Upon doping, we observe emergent hybridization reminiscent of the Zhang-Rice singlet via the oxygen-projected states, modification of the Nd 5d states, and the systematic evolution of Ni 3d hybridization and filling. These experimental data provide direct evidence for the multiband electronic structure of the superconducting infinite-layer nickelates, particularly via the effects of hole doping on not only the oxygen but also nickel and rare-earth bands.
最近在[Formula: see text]中观察到的超导性引起了关于其底层电子结构层次的基本问题。计算表明，该系统属于莫特-哈伯德区，而不是其他镍氧化物和超导铜酸盐的电荷转移构型。在这里，我们使用最先进的局部分辨电子能量损失谱直接探测[Formula: see text]的莫特-哈伯德特性。在掺杂时，我们通过氧投影态、Nd 5d 态的修饰以及 Ni 3d 杂化和填充的系统演化，观察到类似 Zhang-Rice 单重态的新兴杂化。这些实验数据为超导无限层镍酸盐的多带电子结构提供了直接证据，特别是通过空穴掺杂对氧以及镍和稀土带的影响。
