Chauhan, Nagendra S. and Bhasker, Gahtori and Bathula, Sivaiah and Mahanti, Subhendra D. and Dhar, Ajay and Bhattacharya, Amrita (2018) Modulating the lattice dynamics of n-type Heusler compounds via tuning Ni concentration. Applied Physics Letters, 113 (1). 013902-013907. ISSN 0003-6951

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Abstract

Reducing the lattice thermal conductivity (kappa(L)) comprises one of the crucial aspects of thermoelectric research. Ternary intermetallic half Heusler compounds have revealed properties promising for thermoelectric applications. Studies have shown that self doping with Ni in Ni based half Heuslers leads to unprecedented lowering in the kappa(L). Although the underlying physical mechanisms have not been explored in detail, with ZrNiSn as a case study, we experimentally investigate the change in kappa(L) with increase in the Ni concentration in Ni based n-type half Heusler alloys. We observe that at excess Ni doping of 3% in the half Heusler lattice, the thermal conductivity reduces by more than 60%. Our density functional theory based analysis on the ongoing phenomena reveals that at ultralow Ni doping, the localized modes of the antisite Ni defect hybridize with the acoustic modes and this plays the most dominant role in scattering of the thermal phonons leading to significant lowering in kappa(L). Our theoretical analysis can be employed for predicting a suitable dopants that may reduce the kappa L prior to the synthesis of the compound in the laboratory.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/s American Institute of Physics.
Subjects:	Applied Physics/Condensed Matter
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	18 Dec 2019 07:16
Last Modified:	18 Dec 2019 07:16
URI:	http://npl.csircentral.net/id/eprint/3766

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