1. Room temperature high thermoelectric performance of Bi-based full-Heusler compounds CsxRb[formula omitted]Bi with strong anharmonicity.
- Author
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Zeng, Shuming, Shen, Qian, Fang, Lei, Gu, Zonglin, Yang, Jinpeng, Li, Geng, Tu, Yusong, and Ni, Jun
- Subjects
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BOLTZMANN'S equation , *ANHARMONIC motion , *PHONON scattering , *HIGH temperatures , *THERMOELECTRIC materials , *THERMOELECTRIC power - Abstract
Bismuth-based compounds have been identified as a class of promising candidates for the realization of high-performance thermoelectrics, derived from their exceptional electrical conductivity and intrinsic low lattice thermal conductivity κ L. Here, we employed first-principles calculations, self-consistent phonon theory, and compressive sensing technique in conjunction with the Boltzmann transport equation to investigate the anharmonic thermoelectric properties of full-heusler bismuth compounds Cs x Rb 3 − x Bi. As the Cs content increases, the κ L of Cs x Rb 3 − x Bi decreases due to impurity scattering effects, and then increases. Among them, at 300 K, Rb 3 Bi has the largest κ L of 0.69 Wm−1K−1, while Cs 2 RbBi has the smallest κ L of 0.45 Wm−1K−1, both of which are lower than the κ L of traditional bismuth-based thermoelectric materials. The ultralow κ L originates from the strong lattice anharmonicity. In addition, the coexistence of high dispersion and flat band edges leads to high thermoelectric power factor at optimal doping concentration. As a result, the largest thermoelectric figure of merit ZT values of 2.59 (4.19) at 300 (500) K were obtained for CsRb 2 Bi at optimal hole doping level. These findings suggest that Cs x Rb 3 − x Bi compounds are superior for thermal management and thermoelectric applications. • At finite temperatures, Cs x Rb 3 − x Bi compounds are not only mechanically stable but also dynamically stable. • The κ L of Rb 3 Bi, CsRb 2 Bi, Cs 2 RbBi, and Cs 3 Bi are 0.69, 0.47, 0.45, and 0.56 Wm−1K−1, respectively, at 300 K. • The p-type doped CsRb 2 Bi exhibits a ZT value of 2.59, while at 500K, the ZT value reaches 4.19. • The ultra-low κ L of CsRb 2 Bi originates from the rattling vibration of Bi atoms, which manifests as an 'avoided crossing' phenomenon. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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