Filling-Fraction Fluctuation Leading to Glasslike Ultralow Thermal Conductivity in Caged Skutterudites

Ren Wei, Geng Huiyuan, Zhang Zihao, and Zhang Lixia
Phys. Rev. Lett. 118, 245901 – Published 14 June 2017
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Abstract

It is generally believed that filling atoms randomly and uniformly distribute in caged crystals, such as skutterudite compounds. Here, we report first-principles and experimental discovery of a multiscale filling-fraction fluctuation in the RFe4Sb12 system. La0.8Ti0.1Ga0.1Fe4Sb12 spontaneously separates into La-rich and La-poor skutterudite phases, leading to multiscale strain field fluctuations. As a result, glasslike ultralow lattice thermal conductivity approaching the theoretical minimum is achieved, mainly due to strain field scattering of high-energy phonons. These findings reveal that an uneven distribution of filling atoms is efficient to further reduce the lattice thermal conductivity of caged crystals.

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  • Received 16 February 2017

DOI:https://doi.org/10.1103/PhysRevLett.118.245901

© 2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Ren Wei, Geng Huiyuan*, Zhang Zihao, and Zhang Lixia

  • State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China

  • *genghuiyuan@hit.edu.cn
  • zhanglxia@hit.edu.cn

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Issue

Vol. 118, Iss. 24 — 16 June 2017

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