Synthesis and high thermoelectric efficiency of Zintl phase YbCd2-xZnxSb2

We synthesized a series of polycrystalline YbCd2-xZnxSb2 (x=0, 0.4, 0.8, 1, 1.2, 1.6, and 2) samples and measured their thermoelectric properties. Thermoelectric figure of merit ZT at 700 K is higher than 1.0 for Cd-rich samples (x=0, 0.4, 0.8, and 1.0) and Zn substitute of Cd in YbCd2Sb2 can easily tune carrier concentration and reduce thermal conductivity. When x=0.4, sample exhibits the highest power factor (12-20 mu W cm(-1) K-2), the lowest lattice thermal conductivity (1.0 W m(-1) K-1 at 300 K), highest ZT (1.2 at 700 K), and best self-compatibility. The first principles calculations were performed to study the influences of bonding and electronic structures on physical properties.