(Springer Science and Business Media LLC, 2021-11-22) Pan, Grace; Ferenc Segedin, Dan; LaBollita, Harrison; Song, Qi; Nica, Emilian M.; Goodge, Berit H.; Pierce, Andrew T.; Doyle, Spencer; Novakov, Steve; Córdova Carrizales, Denisse; N'Diaye, Alpha T.; Shafer, Padraic; Paik, Hanjong; Heron, John T.; Mason, Jarad A.; Yacoby, Amir; Kourkoutis, Lena F.; Erten, Onur; Brooks, Charles M.; Botana, Antia S.; Mundy, Julia A.
Since the discovery of high-temperature superconductivity in copper oxide (cuprate) materials, there has been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials. One prime materials platform has been the rare-earth nickelates and indeed superconductivity was recently discovered in the doped compound Nd0.8Sr0.2NiO2. Undoped NdNiO2 belongs to a series of layered square-planar nickelates with chemical formula Ndn+1NinO2n+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 (d8.8) 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 behavior. In engineering a distinct superconducting nickelate, we identify the square-planar nickelates as a new family of superconductors which can be tuned via both doping and dimensionality.
