Tsai, Yi-FenYi-FenTsaiWei, Pai-ChunPai-ChunWeiChang, LiuwenLiuwenChangWang, Kuang-KuoKuang-KuoWangYang, Chun-ChuenChun-ChuenYangLai, Yen-ChungYen-ChungLaiHsing, Cheng-RongCheng-RongHsingWei, Ching-MingChing-MingWeiHe, JianJianHeSnyder, G. JeffreyG. JeffreySnyderHSIN-JAY WU2024-09-182024-09-182021https://www.scopus.com/record/display.uri?eid=2-s2.0-85096690877&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/721162論文編號: 2005612Phase transition in thermoelectric (TE) material is a double-edged sword—it is undesired for device operation in applications, but the fluctuations near an electronic instability are favorable. Here, Sb doping is used to elicit a spontaneous composition fluctuation showing uphill diffusion in GeTe that is otherwise suspended by diffusionless athermal cubic-to-rhombohedral phase transition at around 700 K. The interplay between these two phase transitions yields exquisite composition fluctuations and a coexistence of cubic and rhombohedral phases in favor of exceptional figures-of-merit zT. Specifically, alloying GeTe by Sb2Te3 significantly suppresses the thermal conductivity while retaining eligible carrier concentration over a wide composition range, resulting in high zT values of >2.6. These results not only attest to the efficacy of using phase transition in manipulating the microstructures of GeTe-based materials but also open up a new thermodynamic route to develop higher performance TE materials in general. © 2020 Wiley-VCH GmbHdisplacive phase transformationgermanium telluridethermoelectric figure of meritjournal article10.1002/adma.2020056122-s2.0-85096690877