Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties
Name
PhysRevB.97.195440.pdf
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1.23 MB
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Adobe PDF
Checksum (MD5)
9505764794f732c5f34e7e2c0aab86bb
Author(s)
Forghani Oozroody, Mojtaba
Hadjiconstantinou, Nicolas
Date Issued
May 2018
Journal
Physical Review B
Publisher
American Physical Society
Citation
Forghani, Mojtaba and Nicolas G. Hadjiconstantinou. "Reconstruction of phonon relaxation times from systems featuring interfaces with unknown properties." Physical Review B 97, 19 (May 2018): 195440 © 2018 American Physical Society
Version
Final published version
Abstract
We present a method for reconstructing the phonon relaxation-time function τ[subscript ω]=τ(ω) (including polarization) and associated phonon free-path distribution from thermal spectroscopy data for systems featuring interfaces with unknown properties. Our method does not rely on the effective thermal-conductivity approximation or a particular physical model of the interface behavior. The reconstruction is formulated as an optimization problem in which the relaxation times are determined as functions of frequency by minimizing the discrepancy between the experimentally measured temperature profiles and solutions of the Boltzmann transport equation for the same system. Interface properties such as transmissivities are included as unknowns in the optimization; however, because for the thermal spectroscopy problems considered here the reconstruction is not very sensitive to the interface properties, the transmissivities are only approximately reconstructed and can be considered as byproducts of the calculation whose primary objective is the accurate determination of the relaxation times. The proposed method is validated using synthetic experimental data obtained from Monte Carlo solutions of the Boltzmann transport equation. The method is shown to remain robust in the presence of uncertainty (noise) in the measurement.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.97.195440
