Crystal symmetry induced structure and bonding manipulation boosting thermoelectric performance of GeTe
Article
Article Title | Crystal symmetry induced structure and bonding manipulation boosting thermoelectric performance of GeTe |
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ERA Journal ID | 201288 |
Article Category | Article |
Authors | Li, Meng (Author), Hong, Min (Author), Tang, Xiao (Author), Sun, Qiang (Author), Lyu, Wan-Yu (Author), Xu, Sheng-Duo (Author), Kou, Liang-Zhi (Author), Dargusch, Matthew (Author), Zou, Jin (Author) and Chen, Zhi-Gang (Author) |
Journal Title | Nano Energy |
Journal Citation | 73, pp. 1-10 |
Article Number | 104740 |
Number of Pages | 10 |
Year | 2020 |
Publisher | Elsevier |
Place of Publication | Netherlands |
ISSN | 2211-2855 |
2211-3282 | |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.nanoen.2020.104740 |
Web Address (URL) | https://www.sciencedirect.com/science/article/abs/pii/S2211285520302974 |
Abstract | Rock-salt structured GeTe has been reckoned as a promising medium temperature thermoelectric material due to its decent thermal conductivity and multiple electronic valence bands that can be easily modified. However, the applications of GeTe-based thermoelectric materials are strongly impeded by their excessive hole concentration and detrimental phase transition, which deteriorates both thermoelectric performance and mechanical robustness. In this study, we simultaneously solve these two issues by co-doping Ti and Sb in GeTe, achieving an ultrahigh figure-of-merit (ZT) of ~2.2 at 725 K with an average ZT over 2.0 plateauing from 625 to 755 K. Our X-ray spectroscopy analysis and electron microscopy investigation, coupled with first-principle calculation, attribute the extraordinary thermoelectric performance of Ge1-x-yTixSbyTe to the synergetic effects of: a) resonant bonding properties induced by symmetrized crystal lattice; b) high Seebeck coefficient and quality factor due to enhanced band degeneracy and effective mass; c) optimized hole concentration by the aliovalent TiGe and SbGe substitution; and d) minimized thermal conductivity due to the evident frequency-selective phonon scattering by diverse types of defects. Our study indicates that manipulating structure and bonding properties by crystal symmetry modification can explore new-type and high-performance thermoelectric candidates in GeTe and its derivatives, as well as other phase-transition materials. |
Keywords | GeTe; Thermoelectric; Crystal symmetry; Bonding properties; Figure-of-merit |
ANZSRC Field of Research 2020 | 401605. Functional materials |
510404. Electronic and magnetic properties of condensed matter; superconductivity | |
Byline Affiliations | University of Queensland |
Centre for Future Materials | |
Queensland University of Technology | |
Institution of Origin | University of Southern Queensland |
Funding source | Australian Research Council (ARC) |
https://research.usq.edu.au/item/q610q/crystal-symmetry-induced-structure-and-bonding-manipulation-boosting-thermoelectric-performance-of-gete
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