Low-temperature transport properties of the mixed-valence semiconductor Ru0.5Pd0.5Sb3

We have measured the transport properties of Ru0.5Pd0.5Sb3 from 300 down to 4 K and compared them to those of the binary-skutterudite antimonides. In particular, the lattice thermal conductivity of this compound is substantially lower than that of CoSb3 and IrSb3. This is attributed to the mixed-valency of ruthenium in this compound. Using near-edge extended absorption fine structure analysis, it is observed that ruthenium in this compound is in the RU(4+)- and Ru2+-valence states in approximately equal proportions. The potential for thermoelectric applications of this material is also discussed. (C) 1996 American Institute of Physics.