We present electronic structure calculations on layered nickelate oxyfluorides derived from the Ruddlesden-Popper aristotype structure in search of unidentified materials that may host nickelate superconductivity. By performing anion exchange of oxygen with fluorine, we create two heteroanionic ${\mathrm{La}}_2{\mathrm{NiO}}_3\mathrm{F}$ polymorphs and stabilize ${\mathrm{Ni}}^{1+}$ in four-coordinate and five-coordinate square planar and square pyramidal geometries, respectively. We further predict chemical reactions with high thermodynamic driving forces to guide their synthesis. These oxyfluorides are weakly correlated antiferromagnetic insulators, and their nonmagnetic phases exhibit quasi-two-dimensional Fermi surfaces dominated by Ni $d_{x^2-y^2}$ states, which strikingly resemble undoped cuprate superconductors. We discuss how the oxyfluoride anion chemistry promotes Ni-O covalency and single-band character that is more similar to the cuprates than homoanionic infinite-layer nickelates. We use our understanding to propose doping strategies and layered ${\mathrm{LaSrNiO}}_2{\mathrm{F}}_2$ and ${\mathrm{La}}_3{\mathrm{Ni}}_2{\mathrm{O}}_4{\mathrm{F}}_3$ nickelate oxyfluorides with tunable electronic and magnetic structures for experimentation.

中文翻译：

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Ni1+在层状镍酸盐中具有非平面配位的杂阴离子稳定性

我们对衍生自 Ruddlesden-Popper 亚里斯多型结构的层状镍酸氟氧化物进行电子结构计算，以寻找可能具有镍酸超导性的未知材料。通过进行氧与氟的阴离子交换，我们产生了两种杂阴离子${拉}_2{\mathrm{氧化镍}}_3\mathrm{F}$多晶型物和稳定化${你}^{1+}$分别为四坐标和五坐标方形平面和方形金字塔几何形状。我们进一步预测具有高热力学驱动力的化学反应以指导其合成。这些氟氧化物是弱相关的反铁磁绝缘体，它们的非磁性相表现出以 Ni 为主的准二维费米面$d_{X^2-y^2}$状态，与未掺杂的铜酸盐超导体惊人地相似。我们讨论了氟氧化物阴离子化学如何促进 Ni-O 共价性和单带特征，与同阴离子无限层镍酸盐相比，它更类似于铜酸盐。我们利用我们的理解来提出兴奋剂策略和分层${\mathrm{镧锶镍氧化物}}_2{\mathrm{F}}_2$和${拉}_3{你}_2{\mathrm{氧}}_4{\mathrm{F}}_3$具有可调谐电子和磁性结构的镍酸氟氧化物用于实验。