Thermoelectric properties of Sr_1-xLa_xPbO₃ (x0.02)

A set of polycrystalline samples of Sr_1-xLa_xPbO₃ (x<0.02) were prepared with special care taken in controlling the La content to within 0.2%. The measured resistivity () and thermopower (S) change systematically with x, and the x-dependences are explained consistently on the basis of a rigid-band picture in a single parabolic band. The carrier concentration evaluated ranges from 10¹⁹ to 10²⁰ cm^-3, while the scattering time and the mobility do not appreciably change with the La substitution. The power factor (S²/) takes a maximum at a carrier concentration of 4 × 10¹⁹ cm^-3, which is nearly the same value as for conventional thermoelectric semiconductors. These data clearly indicate that carrier doping in SrPbO₃ is as controllable as that in conventional semiconductors.