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

A high-throughput method is developed to investigate the superconducting phase diagram of combinatorial (composition-spread) FeSe_1-xTe_x (0\le x\le 1) films under electron doping. Composition-spread FeSe_1-xTe_x films are fabricated on single CaF_2 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_\rm c) in the Se-rich region, reaching values above 40 K. With increasing Te content, both the maximum T_\rm 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.