Osada Motoki, Wang Bai Yang, Goodge Berit H, Harvey Shannon P, Lee Kyuho, Li Danfeng, Kourkoutis Lena F, Hwang Harold Y
Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
Adv Mater. 2021 Nov;33(45):e2104083. doi: 10.1002/adma.202104083. Epub 2021 Sep 18.
The occurrence of unconventional superconductivity in cuprates has long motivated the search for manifestations in other layered transition metal oxides. Recently, superconductivity is found in infinite-layer nickelate (Nd,Sr)NiO and (Pr,Sr)NiO thin films, formed by topotactic reduction from the perovskite precursor phase. A topic of much current interest is whether rare-earth moments are essential for superconductivity in this system. In this study, it is found that with significant materials optimization, substantial portions of the La Sr NiO phase diagram can enter the regime of coherent low-temperature transport (x = 0.14 - 0.20), with subsequent superconducting transitions and a maximum onset of ≈9 K at x = 0.20. Additionally, the unexpected indication of a superconducting ground state in undoped LaNiO is observed, which likely reflects the self-doped nature of the electronic structure. Combining the results of (La/Pr/Nd) Sr NiO reveals a generalized superconducting dome, characterized by systematic shifts in the unit cell volume and in the relative electron-hole populations across the lanthanides.
铜酸盐中非常规超导现象的出现长期以来一直推动着人们在其他层状过渡金属氧化物中寻找其表现形式。最近，在通过钙钛矿前驱体相的拓扑还原形成的无限层镍酸盐（Nd，Sr）NiO和（Pr，Sr）NiO薄膜中发现了超导性。当前备受关注的一个话题是稀土磁矩对于该体系中的超导性是否至关重要。在本研究中，发现通过显著的材料优化，LaₓSr₁₋ₓNiO相图的很大一部分可以进入低温相干输运区域（x = 0.14 - 0.20），随后出现超导转变，并且在x = 0.20时最大起始温度约为9 K。此外，在未掺杂的LaNiO中观察到了超导基态的意外迹象，这可能反映了电子结构的自掺杂性质。结合（La/Pr/Nd）ₓSr₁₋ₓNiO的结果揭示了一个广义的超导穹顶，其特征是整个镧系元素的晶胞体积和相对电子 - 空穴载流子数发生系统变化。
