Superstrengthening Bi2Te3 through Nanotwinning
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Authors
Li, Guodong
Aydemir, Umut
Morozov, Sergey I.
Wood, Max
An, Qi
Zhai, Pengcheng
Zhang, Qingjie
Goddard III, William A.
Snyder, G. Jeffrey
Issue Date
2017
Type
Article
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Abstract
Bismuth telluride (Bi2Te3) based thermoelectric (TE) materials have been commercialized successfully as solid-state power generators, but their low mechanical strength suggests that these materials may not be reliable for long-term use in TE devices. Here we use density functional theory to show that the ideal shear strength of Bi2Te3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi2Te3 is the weak van derWaals interaction between the Te1 coupling two Te1-Bi-Te2-Bi-Te1 five-layer quint substructures. However, we demonstrate here a surprising result that forming twin boundaries between the Te1 atoms of adjacent quints greatly strengthens the interaction between them, leading to a tripling of the ideal shear strength in nanotwinned Bi2Te3 (0.6 GPa) compared to that in the single crystalline material (0.19 GPa). This grain boundary engineering strategy opens a new pathway for designing robust Bi2Te3 TE semiconductors for high-performance TE devices.
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Citation
Li, G., Aydemir, U., Morozov, S. I., Wood, M., An, Q., Zhai, P., … Snyder, G. J. (2017). Superstrengthening
Bi2Te3
through Nanotwinning. Physical Review Letters, 119(8). doi:10.1103/physrevlett.119.085501
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In Copyright (All Rights Reserved)
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ISSN
0031-9007