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Electronic structure and transport in thermoelectric compounds AZn_2Sb_2 (A = Sr, Ca, Yb, Eu)

Toberer, Eric S. and May, Andrew F. and Melot, Brent C. and Flage-Larsen, Espen and Snyder, G. Jeffrey (2010) Electronic structure and transport in thermoelectric compounds AZn_2Sb_2 (A = Sr, Ca, Yb, Eu). Dalton Transactions, 39 (4). pp. 1046-1054. ISSN 1477-9226. https://resolver.caltech.edu/CaltechAUTHORS:20100201-100334204

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Abstract

The AZn_2Sb_2 (P¯3m1, A = Ca, Sr, Eu, Yb) class of Zintl compounds has shown high thermoelectric efficiency (zT ~ 1) and is an appealing system for the development of Zintl structure–property relationships. High temperature transport measurements have previously been conducted for all known compositions except for SrZn_2Sb_2; here we characterize polycrystalline SrZn_2Sb_2 to 723 K and review the transport behavior of the other compounds in this class. Consistent with the known AZn_2Sb_2 compounds, SrZn_2Sb_2 is found to be a hole-doped semiconductor with a thermal band gap ~ 0.27 eV. The Seebeck coefficients of the AZn2Sb2 compounds are found to be described by similar effective mass (m* ~ 0.6 m_e). Electronic structure calculations reveal similar m* is due to antimony p states at the valence band edge which are largely unaffected by the choice of A-site species. However, the choice of A-site element has a dramatic effect on the hole mobility, with the room temperature mobility of the rare earth-based compositions approximately double that found for Ca and Sr on the A site. This difference in mobility is examined in the context of electronic structure calculations.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/b914172cDOIUNSPECIFIED
http://www.rsc.org/publishing/journals/DT/article.asp?doi=b914172cPublisherUNSPECIFIED
ORCID:
AuthorORCID
May, Andrew F.0000-0003-0777-8539
Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:© 2010 Royal Society of Chemistry. Received 15th July 2009; accepted 16th September 2009; first published as an Advance Article on the web 23rd October 2009. EST thanks the Beckman Foundation for support. We thank the DARPA-Nano Materials Program and NASA-JPL for funding and facilities. BCM gratefully thanks J. M. Rondinelli and K. T. Delaney for fruitful discussions regarding the band structure calculations as well as the NSF for support through a Career Award (DMR 0449354) to his research advisor Ram Seshadri at UCSB.
Funders:
Funding AgencyGrant Number
Beckman FoundationUNSPECIFIED
Defense Advanced Research Projects Agency (DARPA)-Nano Materials ProgramUNSPECIFIED
NASA/JPLUNSPECIFIED
NSFDMR 0449354
Issue or Number:4
Record Number:CaltechAUTHORS:20100201-100334204
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20100201-100334204
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17360
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:11 Feb 2010 16:26
Last Modified:09 Mar 2020 13:19

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