Do, Dat T. and Mahanti, S D. and Pulikkoti, Jiji J. (2014) Electronic structure of Zr-Ni-Sn systems: role of clustering and nanostructures in half-Heusler and Heusler limits. Journal of Physics: Condensed Matter, 26 (27). ISSN 0953-8984

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Abstract

Half-Heusler and Heusler compounds have been of great interest for several decades for thermoelectric, magnetic, half-metallic and many other interesting properties. Among these systems, Zr-Ni-Sn compounds are interesting thermoelectrics which can go from semiconducting half-Heusler (HH) limit, ZrNiSn, to metallic Heusler (FH) limit, ZrNi2Sn. Recently Makongo et al (2011 J. Am. Chem. Soc. 133 18843) found that dramatic improvement in the thermoelectric power factor of HH can be achieved by putting excess Ni into the system. This was attributed to an energy filtering mechanism due to the presence of FH nanostructures in the HH matrix. Using density functional theory we have investigated clustering and nanostructure formation in ZrNi1+xSn (0 <= x <= 1) systems near the HH (x = 0) and FH (x = 1) ends and have found that excess Ni atoms in HH tend to stay close to each other and form nanoclusters. On the other hand, there is competing interaction between Ni-vacancies occupying different sites in FH which prevents them from forming vacancy nanoclusters. Effects of nano-inclusions on the electronic structure near HH and FH ends are discussed.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S IOP Publishing.
Uncontrolled Keywords:	nanocluster, thermoelectric, Heusler, electronic structure, defect, energetics
Subjects:	Computer Science Physics
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	01 Oct 2015 05:57
Last Modified:	01 Oct 2015 05:57
URI:	http://npl.csircentral.net/id/eprint/1270

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