Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 25, 2017 | Supplemental Material + Published
Journal Article Open

Superstrengthening Bi_2Te_3 through Nanotwinning

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.

Additional Information

© 2017 American Physical Society. Received 28 June 2017; revised manuscript received 19 July 2017; published 25 August 2017. This work is partially supported by National Basic Research Program of China (973-program) under Project No. 2013CB632505, the 111 Project of China under Project No. B07040, Materials Project by Department of Energy Basic Energy Sciences Program under Grant No. EDCBEE, DOE Contract No. DE-AC02-05CH11231, and China Postdoctoral Science Foundation (408-32200031). We would like to acknowledge the Jet Propulsion Laboratory, California Institute of Technology, as a funding source under a contract with the National Aeronautics and Space Administration, which was supported by the NASA Science Missions Directorate's Radioisotope Power Systems Technology Advancement Program. Q. A. was supported by U.S. Nuclear Regulatory Commission (NRC) under Cooperative Agreement Number NRC-HQ-84-15-G-0028. S. M. was supported by Act 211 Government of the Russian Federation, Contract No. 02.A03.21.0011 and by the Supercomputer Simulation Laboratory of South Ural State University [51]. Support for W. A. G. and the computing was provided by NSF (DMR-1436985).

Attached Files

Published - PhysRevLett.119.085501.pdf

Supplemental Material - Bi2Te3_twin_SI_3.pdf

Files

Bi2Te3_twin_SI_3.pdf
Files (2.6 MB)
Name Size Download all
md5:6a61cafcd5caa4873a012e6db7da30f4
617.3 kB Preview Download
md5:1dff7dcc4f24adcc06691f1cf9c5308b
2.0 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 17, 2023