Superstrengthening Bi2Te3 through Nanotwinning

Guodong Li, Umut Aydemir, Sergey I. Morozov, Max Wood, Qi An*, Pengcheng Zhai, Qingjie Zhang, William A. Goddard, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

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 der Waals interaction between the Te1 coupling two Te1BiTe2BiTe1 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.

Original languageEnglish (US)
Article number085501
JournalPhysical review letters
Volume119
Issue number8
DOIs
StatePublished - Aug 25 2017

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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