Superstrengthening Bi2Te3 through nanotwinning
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
Language
Keywords
Alternative Title
Abstract
Bismuth telluride (Bi_2Te_3) 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 Bi_2Te_3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi_2Te_3 is the weak van der Waals 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 Bi_2Te_3 (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 Bi_2Te_3 TE semiconductors for high-performance TE devices.
Description
Citation
Publisher
American Physical Society
License
In Copyright
Journal
Volume
Issue
PubMed ID
ISSN
0031-9007