Structure and failure mechanism of the thermoelectric CoSb3/TiCoSb interface

Guodong Li, Shiqiang Hao, Umut Aydemir, Max Wood, William A. Goddard, Pengcheng Zhai, Qingjie Zhang*, G. Jeffrey Snyder

*Corresponding author for this work

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The brittle behavior and low strength of CoSb3/TiCoSb interface are serious issues concerning the engineering applications of CoSb3 based or CoSb3/TiCoSb segmented thermoelectric devices. To illustrate the failure mechanism of the CoSb3/TiCoSb interface, we apply density functional theory to investigate the interfacial behavior and examine the response during tensile deformations. We find that both CoSb3(100)/TiCoSb(111) and CoSb3(100)/TiCoSb(110) are energetically favorable interfacial structures. Failure of the CoSb3/TiCoSb interface occurs in CoSb3 since the structural stiffness of CoSb3 is much weaker than that of TiCoSb. This failure within CoSb3 can be explained through the softening of the Sb-Sb bond along with the cleavage of the Co-Sb bond in the interface. The failure mechanism of the CoSb3/TiCoSb interface is similar to that of bulk CoSb3, but the ideal tensile strength and failure strain of the CoSb3/TiCoSb interface are much lower than those of bulk CoSb3. This can be attributed to the weakened stiffness of the Co-Sb framework because of structural rearrangement near the interfacial region.

Original languageEnglish (US)
Pages (from-to)31968-31977
Number of pages10
JournalACS Applied Materials and Interfaces
Volume8
Issue number46
DOIs
StatePublished - Nov 23 2016

Keywords

  • bond breakage
  • ideal strength
  • interfacial structure
  • tensile failure mode
  • thermoelectric

ASJC Scopus subject areas

  • Materials Science(all)

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