High-pressure electronic phase diagrams in FeSe_1-<i>x</i>Te<i>_x</i>

FeSe has attracted much attention because it has a nonmagnetic nematic order. When selenium is substituted by the isovalent element, sulfur, a nematic quantum critical point without magnetism appears. In this respect, FeSe-based materials have been a unique platform for studying the relationship between the nematic phase and the superconductivity. However, in FeSe_1-xS_x, it has been reported that the superconducting properties abruptly change at the nematic end point (x = 0.17) and therfore understanding the role of the nematic fluctuations in superconductivity is complicated.
In this study, we focus on FeSe_1-xTe_x in which selenium is substituted by tellurium. We have synthesized bulk single crystals of FeSe_1-xTe_x (0 < x < 0.55) by using the chemical vapor transport method. The temperature dependence of the electrical resistivity was measured on the FeSe_1-xTe_x crystals under pressure up to 8 GPa. As a result, we have established the three-dimensional electronic phase diagram; temperature against pressure and Te-substitution. In the obtained phase diagram, the superconducting dome emerges close to the nematic phase and far from the magnetic phase, implying that the nematic fuctuations can enhance superconducting transition temperature in this system.