CORRELATIONS BETWEEN STRUCTURE AND THE SUPERCONDUCTING TRANSITION-TEMPERATURE IN CHEVREL PHASE MOLYBDENUM CHALCOGENIDES

The superconducting transition temperatures for Chevrel phase materials, MxMo6X8(M=Pb, Sn, rare eart ..., X = S, Se, Te) show wide variability even for a single phase, e.g. PbMo6S8 with reported Tc's of 9.8-14.7 K. The Tc is shown to be a linear function of the hexagonal crystallographic c a ratio when materials are grouped according to the formal charge on the ternary element M. This correlation is discussed in terms of the electron-phonon coupling and electronic density of states. © 1979.