Superconductivity of transition metal sulfides, selenides, and phosphides with the NaCl structure

The superconducting properties of transition metal sulfides, selenides, and phosphides having the cubic NaCl structure are described. Binary compounds found to be superconducting are ThS, ScSe, ThSe, HfP, and ThP. More detailed information about the known superconductors Zr_1-xS, LuS, Sc_1-xS, YS, and ZrP is presented. Transition temperature was established as a function of composition for Zr-S, Sc-S, and Y-S NaCl-structure systems. Superconductivity at high pressure was determined in several systems. Some low-temperature specific heat capacity results, room-temperature magnetic susceptibility, and electrical resistance measurements between 2 K and room temperature are reported. Some information is presented about the rhombohedrally distorted compounds ZrSe and HfS. Results of NaCl-structure solid solution (metal replacement) synthesis (including superconductivity data) are reported for (Zr, Sc)-S, (Zr, Y)-S, (Zr, Ti)-S, (Zr, Hf)-S, (La, Y)-S and (Y, Th)-S. We find that superconductivity occurs generally in these materials, and that these compounds have much in common with the better known NaCl defect structure carbides and nitrides.