LnPddSb and Lu sub 3 Au sub 3 Sb sub 4: New Thermoelectric Materials

The thermoelectric properties near ambient temperature of half-Heusler alloys based on HoPdSb, DyPdSb, and ErPdSb are reported. The seebeck coefficients are between 60 and 250 mu V/K. The resistivities range between 0.6 and 20 mOMEGA cm, and the majority carriers are p-type. Thermal conductivities are smallest in intentionally disordered materials. The highest ambient temperature ZT obtains is 0.06. Band structure calculations are presented, and are compared to those for ZrNiSn. It is suggested that half-Heusler alloys with 18 electrons per formula unit may represent a large class of thermoelectric materials. The thermoelectric properties of another family of cubic symmetry antimonides, based on Ho sub 3 Au sub 3 Sb sub 4 and Sm sub 3 Au sub 3 Sb sub 4, are also reported.