High-Throughput Synthesis and Phase Evolution of Nd1-xSrxNiO2 Combinatorial Infinite-Layer Superconducting Thin Films.

The infinite-layer nickelates, owing to their structural and electronic analogies to cuprate superconductors, have attracted intense research interest. Hole doping via alkaline-earth substitution can effectively tune their superconducting properties, yet the synthesis of high-quality films remains challenging due to the sensitivity and instability of both perovskite-phase growth and topotactic reduction. Here, we employ a high-throughput approach to synthesize the nickelate combinatorial thin films and decouple these complexities. The hole-doping (Sr) gradient precursor Nd1- xSrxNiO3 (x = 0 - 0.3) films are prepared by a combinatorial laser molecular beam epitaxy method. Fine control of the topotactic reduction has been conducted to systematically investigate the phase transformation from perovskite precursor to infinite-layer film. High-throughput transport mapping reveals the superconducting dome of infinite-layer Nd1- xSrxNiO2 combinatorial film, and further distinguishes the role of residual apical oxygen in the perovskite precursor films. Our findings suggest that the resistivity upturn observed at low temperature for the under-reduced films most likely originates from Anderson localization induced by disorder arising from residual apical oxygen. This high-throughput strategy of the combinatorial films not only provides an efficient pathway for phase-diagram exploration in superconducting nickelates but also clarifies the synergistic interplay between chemical doping and oxygen stoichiometry in governing superconductivity.