Lattice thermal conductivity and spectral phonon scattering in FeVSb-based half-Heusler compounds

¹ State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University 310027 Hangzhou, China
² Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University - 310027 Hangzhou, China
³ Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province, Zhejiang University 310027 Hangzhou, China

^(a) zhutj@zju.edu.cn

Received: 17 August 2013
Accepted: 16 November 2013

Abstract

Alloying and grain refinement have been conducted to reduce the lattice thermal conductivity of FeVSb-based half-Heusler compounds. And the effects of point defect and boundary on phonon scattering are analyzed using the Callaway model. Point defect scattering and boundary scattering, respectively, cut out the high-frequency and low-frequency phonons. Consequently, most of the heat is carried by phonons with mean free path (mfp) in the range of 1–80 nm and 0.6–30 nm at Debye temperature and 650 K, respectively, indicating that further reduction in lattice thermal conductivity should enhance the scattering of phonons with these characteristic mfp.