Normal state and superconducting properties of Rh17S15 and Pd17Se15
The presence of strongly correlated superconductivity in Rh17S15 has been recently established. In this work, we compare the normal and superconducting parameters of (single and polycrystalline) Rh17S15 with those of (polycrystalline) Pd17Se15 which is reported here for the first time to be a superconductor below 2.2?K. Pd17Se15, which is iso-structural to Rh17S15 (space group Pm3m), has very different properties and provides for an interesting study in contrast with Rh17S15. We see that the large unit volume of Pd17Se15 and the large separation of Pd?Pd atoms in its structure as compared to that in pure Pd metal lead to the absence of strong correlations in this compound. Finally, we report band structure calculations on these two compounds and compare the density of states with estimates from heat capacity data. Upper critical field, heat capacity (down to 500?mK), Hall effect and band structure studies suggest that Rh17S15 is a multi-band superconductor.