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Thermoelectric transport trends in group 4 half-Heusler alloys

Berland, Kristian and Shulumba, Nina and Hellman, Olle and Persson, Clas and Løvvik, Ole Martin (2019) Thermoelectric transport trends in group 4 half-Heusler alloys. Journal of Applied Physics, 126 (14). Art. No. 145102. ISSN 0021-8979. https://resolver.caltech.edu/CaltechAUTHORS:20191008-095438424

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Abstract

The thermoelectric properties of 54 different group 4 half-Heusler (HH) alloys have been studied from first principles. Electronic transport was studied with density functional theory using hybrid functionals facilitated by the k⋅p method, while the temperature-dependent effective potential method was used for the phonon contributions to the figure of merit ZT. The phonon thermal conductivity was calculated including anharmonic phonon-phonon, isotope, alloy, and grain-boundary scattering. HH alloys have an XYZ composition, and those studied here are in the group 4-9-15 (Ti,Zr,Hf)(Co,Rh,Ir)(As,Sb,Bi) and group 4-10-14 (Ti,Zr,Hf)(Ni,Pd,Pt)(Ge,Sn,Pb). The electronic part of the thermal conductivity was found to significantly impact ZT and thus the optimal doping level. Furthermore, the choice of functional was found to significantly affect thermoelectric properties, particularly for structures exhibiting band alignment features. The intrinsic thermal conductivity was significantly reduced when alloy and grain-boundary scattering were accounted for, which also reduced the spread in thermal conductivity. It was found that sublattice disorder on the Z-site, i.e., the site occupied by group 14 or 15 elements, was more effective than X-site substitution, occupied by group 4 elements. The calculations confirmed that ZrNiSn, ZrCoSb, and ZrCoBi based alloys display promising thermoelectric properties. A few other n-type and p-type compounds were also predicted to be potentially excellent thermoelectric materials, given that sufficiently high charge carrier concentrations can be achieved. This study provides insight into the thermoelectric potential of HH alloys and casts light on strategies to optimize the thermoelectric performance of multicomponent alloys.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1063/1.5117288DOIArticle
ORCID:
AuthorORCID
Berland, Kristian0000-0002-4655-1233
Shulumba, Nina0000-0002-2374-7487
Hellman, Olle0000-0002-3453-2975
Persson, Clas0000-0002-9050-5445
Løvvik, Ole Martin0000-0002-4169-1544
Additional Information:© 2019 Published under license by AIP Publishing. Submitted: 29 July 2019; Accepted: 21 September 2019; Published Online: 8 October 2019. This paper is part of the special topic on Advanced Thermoelectrics. Computations were performed on the Abel and Stallo high performance cluster through a NOTUR allocation. This work is part of the THELMA project (Project No. 228854) supported by the Research Council of Norway.
Funders:
Funding AgencyGrant Number
Research Council of Norway228854
Issue or Number:14
Record Number:CaltechAUTHORS:20191008-095438424
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20191008-095438424
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99142
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Oct 2019 17:52
Last Modified:08 Oct 2019 17:52

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