Compositional Fluctuations Locked by Athermal Transformation Yielding High Thermoelectric Performance in GeTe.
Snyder, G Jeffrey
Wu, Hsin Jay
KAUST DepartmentPhysical Science and Engineering (PSE) Division
Embargo End Date2021-11-20
Permanent link to this recordhttp://hdl.handle.net/10754/666056
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AbstractPhase 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 Sb2 Te3 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.
CitationTsai, Y., Wei, P., Chang, L., Wang, K., Yang, C., Lai, Y., … Wu, H. (2020). Compositional Fluctuations Locked by Athermal Transformation Yielding High Thermoelectric Performance in GeTe. Advanced Materials, 2005612. doi:10.1002/adma.202005612
SponsorsThe authors acknowledged the financial support from the Young Scholar Fellowship Program by Ministry of Science and Technology (MOST) in Taiwan, under Grant MOST 108-2636-E-110-001.
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