Abstract
Polycrystalline-sintered samples of beta-KxBa1-xCu2S2 have been synthesized by melting in sealed quartz ampoules. Beta phase is obtained by quenching from 973 K to room temperature. The crystal structure of the samples has been determined by a powder X-ray diffraction (XRD) method. The electrical resistivity and Seebeck coefficient of beta-BaCu2S2 increase with increasing temperature. The temperature dependence of the electrical resistivity of beta-KxBa1-xCu2S2 shows the metallic behavior with increasing x value, resulting in the generation of holes in the valence band. Beta-BaCu2S2 shows extremely low thermal conductivity, about 0.6 W/m/K at room temperature. The dimensionless figure of merit ZT of beta-BaCu2S2 shows relatively high value, 0.37 at 800 K.
