Superconductivity in S-substituted FeTe

We synthesized a superconducting system of FeTe1−xSx with a PbO-type structure. It has the simplest crystal structure among iron-based superconductors. The superconducting transition temperature is about 10 K when x is 0.2. The upper critical field Bc2(0) was estimated to be ~70 T. The coherent length was calculated to be ~2.2 nm. Since FeTe1−xSx is composed of nontoxic elements, this material is a candidate for applications that will further advance research on iron-based superconductors.