High-Throughput Synthesis and Phase Evolution of Nd_1-xSr_xNiO₂ 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 Nd_{1- x}Sr_xNiO₃ (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 Nd_{1- x}Sr_xNiO₂ 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.