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Title: Enhanced Thermoelectric Performance in 18-Electron Nb 0.8 CoSb Half-Heusler Compound with Intrinsic Nb Vacancies

Authors:
 [1];  [1];  [2];  [2];  [1];  [1];  [1]; ORCiD logo [1]
  1. State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 China
  2. Department of Materials Science and Engineering, Northwestern University, Evanston IL 60208 USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1416251
Grant/Contract Number:
SC0001299
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Advanced Functional Materials
Additional Journal Information:
Related Information: CHORUS Timestamp: 2018-01-09 19:29:23; Journal ID: ISSN 1616-301X
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
Germany
Language:
English

Citation Formats

Xia, Kaiyang, Liu, Yintu, Anand, Shashwat, Snyder, G. Jeffrey, Xin, Jiazhan, Yu, Junjie, Zhao, Xinbing, and Zhu, Tiejun. Enhanced Thermoelectric Performance in 18-Electron Nb 0.8 CoSb Half-Heusler Compound with Intrinsic Nb Vacancies. Germany: N. p., 2018. Web. doi:10.1002/adfm.201705845.
Xia, Kaiyang, Liu, Yintu, Anand, Shashwat, Snyder, G. Jeffrey, Xin, Jiazhan, Yu, Junjie, Zhao, Xinbing, & Zhu, Tiejun. Enhanced Thermoelectric Performance in 18-Electron Nb 0.8 CoSb Half-Heusler Compound with Intrinsic Nb Vacancies. Germany. doi:10.1002/adfm.201705845.
Xia, Kaiyang, Liu, Yintu, Anand, Shashwat, Snyder, G. Jeffrey, Xin, Jiazhan, Yu, Junjie, Zhao, Xinbing, and Zhu, Tiejun. 2018. "Enhanced Thermoelectric Performance in 18-Electron Nb 0.8 CoSb Half-Heusler Compound with Intrinsic Nb Vacancies". Germany. doi:10.1002/adfm.201705845.
@article{osti_1416251,
title = {Enhanced Thermoelectric Performance in 18-Electron Nb 0.8 CoSb Half-Heusler Compound with Intrinsic Nb Vacancies},
author = {Xia, Kaiyang and Liu, Yintu and Anand, Shashwat and Snyder, G. Jeffrey and Xin, Jiazhan and Yu, Junjie and Zhao, Xinbing and Zhu, Tiejun},
abstractNote = {},
doi = {10.1002/adfm.201705845},
journal = {Advanced Functional Materials},
number = ,
volume = ,
place = {Germany},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 5, 2019
Publisher's Accepted Manuscript

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  • Cited by 5
  • The electronic structure and transport properties of the half-Heusler compound CoVSn are studied in this paper systematically by combining first-principles electronic structure calculations and Boltzmann transport theory. The band structure at the valence-band edge is complex with multiple maxima derived from hybridized transition element d states. The result is a calculated thermopower larger than 200 μV /Κ within a wide range of doping concentrations and temperatures for heavily doped p-type CoVSn. The thermoelectric properties additionally benefit from the corrugated shapes of the hole pockets in our calculated isoenergy surfaces. Our calculated power factor S 2σ/τ (with respect to an averagemore » unknown scattering time) of CoVSn is comparable to that of FeNbSb. A smaller lattice thermal conductivity can be expected from the smaller group velocities of acoustical modes compared to FeNbSb. Finally, overall, good thermoelectric performance for CoVSn can be expected by considering the electronic transport and lattice thermal conductivity.« less
    Cited by 5
  • The 18-electron rule is a widely used criterion in the search for new half-Heusler thermoelectric materials. However, several 19-electron compounds such as NbCoSb have been found to be stable and exhibit thermoelectric properties rivaling state-of-the art materials. Using synchrotron X-ray diffraction and density functional theory calculations, we show that samples with nominal (19-electron) composition NbCoSb actually contain a half-Heusler phase with composition Nb0.84CoSb. The large amount of stable Nb vacancies reduces the overall electron count, which brings the stoichiometry of the compound close to an 18-electron count, and stabilizes the material. Excess electrons beyond 18 electrons provide heavy doping neededmore » to make these good thermoelectric materials. This work demonstrates that considering possible defect chemistry and allowing small variation of electron counting leads to extra degrees of freedom for tailoring thermoelectric properties and exploring new compounds. Here we discuss the 18-electron rule as a guide to find defect-free half-Heusler semiconductors. Other electron counts such as 19-electron NbCoSb can also be expected to be stable as n-type metals, perhaps with cation vacancy defects to reduce the electron count.« less