Ballistic length scale of heat transport in the subwavelength limit

ORAL

Abstract

We present a comprehensive study of phonon ballistic length scale using a Casimir--Rayleigh model of heat transport. This model incorporates temperature-dependent Casimir radiation and wavelength-dependent Rayleigh scattering. We exploit this definition to understand heat transport in newly synthesized silicon metalattices, which consist of a finely controlled, three-dimensional arrangement of nanometer-sized cavities in crystalline silicon. Through computational simulation and experimental validation, we show that the heat conductivity of metalattices exhibits a minimum as a function of the cavity diameter at constant porosity. This departure from Casimir's linear scaling law can be understood in terms of the geometry dependence of the phonon mean free path in a network of cavities.

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Presenters

  • Weinan Chen

    Materials Science and Engineering Department, Pennsylvania State University

Authors

  • Weinan Chen

    Materials Science and Engineering Department, Pennsylvania State University

  • Disha Talreja

    Materials Science and Engineering Department, Pennsylvania State University

  • Hiu Yan Cheng

    Department of Chemistry, Pennsylvania State University

  • Gerald D Mahan

    Physics, Pennsylvania State University, Department of Physics, Pennsylvania State University

  • Vincent Henry Crespi

    Pennsylvania State University, Department of Physics, Pennsylvania State University

  • John Badding

    Department of Chemistry, Pennsylvania State University

  • Venkatraman Gopalan

    Pennsylvania State University, Materials Science and Engineering, Pennsylvania State University, Physics, Pennsylvania State University, Materials Science and Engineering Department, Pennsylvania State University

  • Ismaila Dabo

    Pennsylvania State University, Materials Science and Engineering Department, Pennsylvania State University, Materials Science and Engineering, Pennsylvania State University