Large Anharmonicity and Low Lattice Thermal Conductivity of Thermoelectric Sn(SbTe2)2

Very recently, it has been reported that Sn(SbTe2)(2) exhibits a low kappa(lat) (approximate to 0.46 W m(-1) K-1 at 720 K), thus making Sn(SbTe2)(2) a good thermoelectric material. The low kappa(lat) is thought to be due to the anharmonicity of the lattice, but no experimental evidence for this has been reported. Herein, the origin of such low kappa(lat) in Sn(SbTe2)(2) is experimentally investigated by measuring various physical properties and the linear thermal expansion coefficient. The results show that the Gruneisen parameter of Sn(SbTe2)(2) is very high, 3.38, which means that Sn(SbTe2)(2) has a large anharmonicity. Due to this large anharmonicity, the Sn(SbTe2)(2) sample shows a very low kappa(lat) and a relatively high thermoelectric figure of merit zT of 0.32 at 770 K.

Automated summary

The study shows that Sn(SbTe2)(2) has a large anharmonicity, leading to its low thermal conductivity, making it an excellent thermoelectric material with relatively high thermoelectric figure of merit.