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

Junphil Hwang, Marco Fornari, Rabih Al Rahal Al Orabi, Chan Chieh Lin, Régis Gautier, Bruno Fontaine, Woochul Kim, Jong Soo Rhyee, Daehyun Wee

Research output: Contribution to journalArticle

76 Scopus citations

Abstract

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 ∼1 at 873 K in Sn0.96Ga0.07Te, which corresponds to an ∼80% improvement with respect to pure SnTe.

Original languageEnglish
Pages (from-to)612-620
Number of pages9
JournalChemistry of Materials
Volume29
Issue number2
DOIs
StatePublished - Jan 24 2017

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