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Structural failure of layered thermoelectric In₄Se_(3-δ) semiconductors is dominated by shear slippage

Huang, Min and Li, Guodong and An, Qi and Zhai, Pengcheng and Goddard, William A., III (2020) Structural failure of layered thermoelectric In₄Se_(3-δ) semiconductors is dominated by shear slippage. Acta Materialia, 187 . pp. 84-90. ISSN 1359-6454. https://resolver.caltech.edu/CaltechAUTHORS:20200128-125810051

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Abstract

In₄Se_(3-δ) semiconductors exhibit high zT as an n-type TE material, making them promising materials for thermoelectric (TE) applications. However, their commercial applications have been limited by the degradation of their mechanical properties upon cyclic thermal loading, making it important to understand their stress response under external loadings. Thus we applied molecular dynamics (MD) simulations using a density functional theory (DFT) derived force field to investigate the stress response and failure mechanism of In₄Se_(3-δ) under shear loading as a function of strain rates and temperatures. We considered the most plausible slip system (001)/<100> based on the calculations. We find that shear slippage among In/Se layered structures dominates the shear failure of In₄Se_(3-δ). Particularly, Se vacancies promote disorder of the In atoms in the shear band, which accelerates the shear failure. With increasing temperature, the critical failure strength of In4Se3 and the fracture strain of In₄Se₃ decrease gradually. In contrast, the fracture strain of In₄Se_(2.75) is improved although the ultimate strength decreases as temperature increases, suggesting that the Se vacancies enhance the ductility at high temperature. In addition, the ultimate strength and the fracture strain for In₄Se_(2.75) increase slightly with the strain rate. This strain rate effect is more significant at low temperature for In₄Se_(2.75) because of the Se vacancies. These findings provide new perspectives of intrinsic failure of In₄Se_(3-δ) and theory basis for developing robust In₄Se_(3-δ) TE devices.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.actamat.2020.01.045DOIArticle
ORCID:
AuthorORCID
Li, Guodong0000-0002-4761-6991
An, Qi0000-0003-4838-6232
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2020 Acta Materialia Inc. Published by Elsevier Ltd. Received 30 November 2019, Revised 22 January 2020, Accepted 22 January 2020, Available online 27 January 2020. This work was supported by the National Natural Science Foundation of China (No. 51972253, 51772231); the Hubei Provincial Natural Science Foundation of China (2018CFB646); and the Fundamental Research Funds for the Central Universities (No. WUT 2019IVA055, 2019IB006). We acknowledge Sandia National Laboratories for distributing the open-source MD software LAMMPS. Wag was supported by the US NSF (CBET-1805022). The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China51972253
National Natural Science Foundation of China51772231
Hubei Provincial Natural Science Foundation of China2018CFB646
Fundamental Research Funds for the Central Universities2019IVA055
Fundamental Research Funds for the Central Universities2019IB006
NSFCBET-1805022
Subject Keywords:Mechanical properties; Layered In4Se3; Fracture mechanism; Strain rate sensitivity; Temperature effect
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1365
Record Number:CaltechAUTHORS:20200128-125810051
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200128-125810051
Official Citation:Min Huang, Guodong Li, Qi An, Pengcheng Zhai, William A. Goddard, Structural failure of layered thermoelectric In4Se3-δ semiconductors is dominated by shear slippage, Acta Materialia, Volume 187, 2020, Pages 84-90, ISSN 1359-6454, https://doi.org/10.1016/j.actamat.2020.01.045. (http://www.sciencedirect.com/science/article/pii/S1359645420300707)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:100964
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 Jan 2020 23:33
Last Modified:06 Feb 2020 17:55

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