Thermoelectric Properties of Polycrystalline SrZn2Sb2 Prepared by Spark Plasma Sintering

Compact polycrystalline samples of SrZn2Sb2 [space group P (3) over bar m1, a = 4.503(1) angstrom, c = 7.721(1) angstrom] were prepared by spark plasma sintering. Thermoelectric performance, Hall effect, and magnetic properties were investigated in the temperature range from 2 K to 650 K. The thermoelectric figure of merit ZT was found to increase with temperature up to ZT = 0.15 at 650 K. At this temperature the material showed a high Seebeck coefficient of + 230 mu VK-1, low thermal conductivity of 1.3 W m(-1) K-1, but rather low electrical conductivity of 54 S cm(-1), together with a complex temperature behavior. SrZn2Sb2 is a diamagnetic p-type conductor with a carrier concentration of 5 x 10(18) cm(-3) at 300 K. The electronic structure was calculated within the density-functional theory (DFT), revealing a low density of states (DOS) of 0.43 states eV(-1) cell(-1) at the Fermi level.