Since the discovery of high-temperature superconductivity in copper oxide materials¹, there have been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials². One prime materials platform has been the rare-earth nickelates and, indeed, superconductivity was recently discovered in the doped compound Nd_0.8Sr_0.2NiO₂ (ref. ³). Undoped NdNiO₂ belongs to a series of layered square-planar nickelates with chemical formula Nd_n+1Ni_nO_2n+2 and is known as the ‘infinite-layer’ (n = ∞) nickelate. Here we report the synthesis of the quintuple-layer (n = 5) member of this series, Nd₆Ni₅O₁₂, in which optimal cuprate-like electron filling (d^8.8) is achieved without chemical doping. We observe a superconducting transition beginning at ~13 K. Electronic structure calculations, in tandem with magnetoresistive and spectroscopic measurements, suggest that Nd₆Ni₅O₁₂ interpolates between cuprate-like and infinite-layer nickelate-like behaviour. In engineering a distinct superconducting nickelate, we identify the square-planar nickelates as a new family of superconductors that can be tuned via both doping and dimensionality.

自从在氧化铜材料中发现高温超导性¹以来，一直在努力了解这一阶段的起源并发现新的类铜酸盐超导材料²。一种主要材料平台是稀土镍酸盐，事实上，最近在掺杂化合物 Nd _0.8 Sr _0.2 NiO ₂中发现了超导性（参考文献³）。未掺杂的 NdNiO ₂属于一系列层状的方形平面镍酸盐，化学式为 Nd _{n +1} Ni _n O _{2 n +2}，被称为“无限层”（n =  ∞ ) 镍酸盐。在这里，我们报告了该系列的五层 ( n  = 5) 成员 Nd ₆ Ni ₅ O ₁₂的合成，其中在没有化学掺杂的情况下实现了最佳的类铜酸盐电子填充 ( d ^{8.8 )。}我们观察到从~13 K 开始的超导转变。电子结构计算与磁阻和光谱测量相结合，表明 Nd ₆ Ni ₅ O ₁₂在类铜酸盐和无限层类镍酸盐行为之间进行插值。在设计一种独特的超导镍酸盐时，我们将方形平面镍酸盐确定为一个新的超导体家族，可以通过掺杂和维度进行调整。