Nanophononic metamaterial: thermal conductivity reduction by local resonance

We present the concept of a locally resonant nanophononic metamaterial for thermoelectric energy conversion. Our configuration, which is based on a silicon thin film with a periodic array of pillars erected on one or two of the free surfaces, qualitatively alters the base thin-film phonon spectrum d...

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Bibliographic Details
Published in:Physical review letters 2014-02, Vol.112 (5), p.055505-055505, Article 055505
Main Authors: Davis, Bruce L, Hussein, Mahmoud I
Format: Article
Language:English
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Summary:We present the concept of a locally resonant nanophononic metamaterial for thermoelectric energy conversion. Our configuration, which is based on a silicon thin film with a periodic array of pillars erected on one or two of the free surfaces, qualitatively alters the base thin-film phonon spectrum due to a hybridization mechanism between the pillar local resonances and the underlying atomic lattice dispersion. Using an experimentally fitted lattice-dynamics-based model, we conservatively predict the metamaterial thermal conductivity to be as low as 50% of the corresponding uniform thin-film value despite the fact that the pillars add more phonon modes to the spectrum.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.112.055505