论文标题
$ d^{9-δ} $多层镍的新兴平坦物理
Emergent flat-band physics in $d^{9-δ}$ multilayer nickelates
论文作者
论文摘要
最近的实验表明，减少的多层稀土（Re）形式的镍氧化物re $ _ {p+1} $ ni $ _p $ o $ $ _ {2p+2} $可能属于超导导兰植物镍的新颖家族。在这里，Pr $ _ {4} $ ni $ _3 $ o $ o $ _ {8} $和nd $ _ {6} $ ni $ _5 $ _5 $ o $ o $ _ {12} $的相关电子结构是通过先进的真实性多体框架研究的。据透露，两个系统的低能物理学都由Ni-$ d_ {x^2-y^2} $的相互作用和ni- $ d_ {z^2} $自由度。虽然Ni- $ d_ {x^2-y^2} $轨道总是高度相关的（轨道选择性的）Mott-Mott usulations unculatime，但ni- $ d_ {z^2} $ orbitals引起了吸引人的非杂物性功能。在低温下，PR化合物仍然显示QP的Ni-$ d_ {x^2-y^2} $ - 在费米级别衍生的状态，但是ND化合物的相互作用的费米学被急剧的NI-$ d_ {z^2} $ - 控制平面频带。这些发现很好地转化为先前掺杂的无限层镍盐的表征，因此进一步证明了一种非常规超导性机制的理由，这与高$ t _ {\ rm c} $ cuprates中的高含量不同。
Recent experiments have shown that the reduced multilayer rare-earth (RE) nickel oxides of form RE$_{p+1}$Ni$_p$O$_{2p+2}$ may belong to the novel family of superconducting lanthanide nickelates. Here, the correlated electronic structure of Pr$_{4}$Ni$_3$O$_{8}$ and Nd$_{6}$Ni$_5$O$_{12}$ is studied by means of an advanced realistic many-body framework. It is revealed that the low-energy physics of both systems is dominated by an interplay of Ni-$d_{x^2-y^2}$ and Ni-$d_{z^2}$ degrees of freedom. Whilst the Ni-$d_{x^2-y^2}$ orbitals are always highly correlated near an (orbital-selective) Mott-insulating regime, the Ni-$d_{z^2}$ orbitals give rise to intriguing non-dispersive features. At low temperature, the Pr compound still displays QP-like Ni-$d_{x^2-y^2}$-derived states at the Fermi level, but the interacting fermiology of the Nd compound is outshined by an emergent Ni-$d_{z^2}$-controlling flat band. These findings translate well to the previous characterization of doped infinite-layer nickelates, and hence further make the case for a mechanism of unconventional superconductivity which is distinct from the one in high-$T_{\rm c}$ cuprates.
