Origins of ultralow thermal conductivity in 1-2-1-4 quaternary selenides

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2019, Vol.7 (6), p.2589-2596
• Main Authors: Kuo, Jimmy Jiahong, Aydemir, Umut, Pöhls, Jan-Hendrik, Zhou, Fei, Yu, Guodong, Faghaninia, Alireza, Ricci, Francesco, White, Mary Anne, Rignanese, Gian-Marco, Hautier, Geoffroy, Jain, Anubhav, Snyder, G. Jeffrey
• Format: Article
• Language: English
• Subjects: Bonding strength; Density functional theory; Dimers; Electrical conductivity; Electrical resistivity; Heat conductivity; Heat transfer; Interstitials; MATERIALS SCIENCE; Mathematical analysis; Selenide; Selenides; Thermal conductivity; Thermal properties; Thermodynamic properties; Transport properties
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c8ta09660k

Engineering the thermal properties in solids is important for both fundamental physics ( e.g. electric and phonon transport) and device applications ( e.g. thermal insulating coating, thermoelectrics). In this paper, we report low thermal transport properties of four selenide compounds (BaAg 2 SnSe 4 , BaCu 2 GeSe 4 , BaCu 2 SnSe 4 and SrCu 2 GeSe 4 ) with experimentally-measured thermal conductivity as low as 0.31 ± 0.03 W m −1 K −1 at 673 K for BaAg 2 SnSe 4 . Density functional theory calculations predict κ < 0.3 W m −1 K −1 for BaAg 2 SnSe 4 due to scattering from weakly-bonded Ag-Ag dimers. Defect calculations suggest that achieving high hole doping levels in these materials could be challenging due to monovalent ( e.g. , Ag) interstitials acting as hole killers, resulting in overall low electrical conductivity in these compounds. Low thermal conductivity of BaAb 2 SnSe 4 is measured, which can be attributed to the weakly-bonded Ag-Ag dimers.