Electronic phase diagram of FeSe_1-xTe_x under high pressure

FeSe has the simplest crystal structure among the iron-based superconductors and is known to have a nonmagnetic nematic order. When selenium is substituted by the isovalent element, sulfur, the nematic phase is suppressed and a nematic quantum critical point without magnetism appears. On the other hand, under pressure, a dome-shaped magnetic phase is induced and the superconducting transition temperature rises from 9 K to 37 K.
In this study, we focus on FeSe_1-xTe_x in which selenium is substituted by tellurium. In order to clarify the relationship between the nematic phase and the superconducting phase, we have synthesized bulk single crystals of FeSe_1-xTe_x (0<x<0.22) 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 using a constant loading cubic anvil high-pressure apparatus. As a result, we have established the three-dimensional electronic phase diagram; temperature against pressure and Te-substitution. The obtained phase diagram indicates that the tellurium substitution shifts the pressure-induced magnetic phase to a lower pressure side, which is in contrast to the sulfur substitution case.