High-Throughput Mapping of the Superconducting Phase Diagram Combining Composition-Spread FeSe_1−xTe_x Film with Carrier Doping

Abstract A high-throughput method is developed to investigate the superconducting phase diagram of combinatorial (composition-spread) FeSe_1−xTe_x (0 ≤ x ≤ 1) films under electron doping. Composition-spread FeSe_1−xTe_x films are fabricated on single CaF₂ substrates using combinatorial laser molecular beam epitaxy. An integrated device structure combining ionic-liquid gating with FeSe_1−xTe_x films enables simultaneous transport measurements over the whole composition range. Electrochemical gating significantly enhances the superconducting transition temperature (T_c) in the Se-rich region, reaching values above 40 K. With increasing Te content, both the maximum T_c and the gating efficiency gradually decrease. A comprehensive two-dimensional superconducting phase diagram is constructed as a function of Te content and doping level. These results establish an ideal approach for rapidly exploring the correlation between chemical composition, carrier doping, and superconductivity in Fe-based superconductors.