Ultralow Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in SnTe:Ga Materials

Rabih Al Rahal Al Orabi (1, 2) , Junphil Hwang (3) , Chan-Chieh Lin (4) , Regis Gautier (5) , Bruno Fontaine (5) , Woochul Kim (3) , Jong-Soo Rhyee (4) , Daehyun Wee (1) , Marco Fornari (2)

1 EWHA - EWHA Womans University
2 CMU - Central Michigan University
3 Yonsei University
4 Department of Applied Physics
5 ISCR - Institut des Sciences Chimiques de Rennes

Ultralow thermal conductivity is of great interest in a variety of fields, including thermoelectric energy conversion. We report, for the first time, experimental evidence that Ga-doping in SnTe may lower the lattice thermal conduction slightly below the theoretical amorphous minimum at high temperature. Such an effect is justified by the spontaneous formation of nanoprecipitates we characterized as GaTe. Remarkably, the introduction of Ga (2-10%) in SnTe also improves the electronic transport properties by activating several hole pockets in the multivalley valence band. Experimental results are supported by density functional theory calculations. The thermoelectric figure of merit, ZT, reaches similar to 1 at 873 K in Sn0.96Ga0.07Te, which corresponds to an similar to 80% improvement with respect to pure SnTe.

Domains: Chemical Sciences; Material chemistry

Rabih Al Rahal Al Orabi, Junphil Hwang, Chan-Chieh Lin, Regis Gautier, Bruno Fontaine, et al.. Ultralow Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in SnTe:Ga Materials. Chemistry of Materials, 2017, 29 (2), pp.612--620. ⟨10.1021/acs.chemmater.6b04076⟩. ⟨hal-01500409⟩