Superconducting properties of Tl-doped PbTe

Tl-doped PbTe (Pb_{1-x}Tl_{x}Te) is an anomalous superconductor with a remarkably high maximum T_c value given its relatively low carrier concentration. Here, we present results of systematic measurements of superconducting parameters for this material, for Tl concentrations up to x = 1.4%. We find that it is a Type II, weak-coupled BCS superconductor in the dirty limit and discuss implications for the applicability of the charge Kondo model recently proposed to account for superconductivity in this system.