Thermoelectric Properties of Polycrystalline SrZn2Sb2 Prepared by Spark Plasma Sintering

Compact polycrystalline samples of SrZn2Sb2 [space group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ P\overline{3} m1 $$\end{document}, a = 4.503(1) Å, c = 7.721(1) Å] 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 μV K−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 × 1018 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.