Superconducting phase diagram of multilayer square-planar nickelates.

Pan, Grace A; Segedin, Dan Ferenc; TenHuisen, Sophia F R; Bhatt, Lopa; LaBollita, Harrison; Jiang, Abigail Y; Song, Qi; Turkiewicz, Ari B et al. · Science · 2026

basic_science · Level V

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Abstract

The discovery of superconductivity in square-planar nickelates has offered a rich materials platform to explore the origins of high-temperature superconductivity. However, experimental investigations have largely been limited to the infinite-layer <i>R</i>NiO<sub>2</sub> (<i>R</i>, rare earth) nickelates. We constructed a phase diagram of multilayer square-planar Nd<i><sub>n</sub></i><sub>+1</sub>Ni<i><sub>n</sub></i>O<sub>2</sub><i><sub>n</sub></i><sub>+2</sub> compounds and found signatures of superconductivity for dimensionality <i>n</i> = 4 to 8. Upon decreasing <i>n</i>, the superconducting anisotropy evolves owing to 4<i>f</i> electron effects, and electronic structure characteristics approach cuprate-like behavior. Magnetic fluctuations persist from within the superconducting regime and into the overdoped, nonsuperconducting regime. The superconducting regime overlaps with that of chemically doped infinite-layer nickelates, demonstrating underlying commonalities as well as differences across varying structural realizations of square-planar nickelates. Our work establishes this layered template for creating new nickel-based superconductors.