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Heat dissipation in the quasiballistic regime studied using the Boltzmann equation in the spatial frequency domain

Hua, Chengyun and Minnich, Austin J. (2018) Heat dissipation in the quasiballistic regime studied using the Boltzmann equation in the spatial frequency domain. Physical Review B, 97 (1). Art. No. 014307. ISSN 2469-9950. http://resolver.caltech.edu/CaltechAUTHORS:20180110-101836591

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Abstract

Quasiballistic heat conduction, in which some phonons propagate ballistically over a thermal gradient, has recently become of intense interest. Most works report that the thermal resistance associated with nanoscale heat sources is far larger than predicted by Fourier's law; however, recent experiments show that in certain cases the difference is negligible despite the heaters being far smaller than phonon mean-free paths. In this work, we examine how thermal resistance depends on the heater geometry using analytical solutions of the Boltzmann equation. We show that the spatial frequencies of the heater pattern play the key role in setting the thermal resistance rather than any single geometric parameter, and that for many geometries the thermal resistance in the quasiballistic regime is no different than the Fourier prediction. We also demonstrate that the spectral distribution of the heat source also plays a major role in the resulting transport, unlike in the diffusion regime. Our work provides an intuitive link between the heater geometry, spectral heating distribution, and the effective thermal resistance in the quasiballistic regime, a finding that could impact strategies for thermal management in electronics and other applications.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevB.97.014307DOIArticle
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.97.014307PublisherArticle
https://arxiv.org/abs/1711.04212arXivDiscussion Paper
Additional Information:© 2018 American Physical Society. Received 10 November 2017; revised manuscript received 21 December 2017; published 10 January 2018. C.H.'s research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Deparment of Energy.
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Department of Energy (DOE)UNSPECIFIED
Record Number:CaltechAUTHORS:20180110-101836591
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180110-101836591
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84228
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:10 Jan 2018 18:52
Last Modified:10 Jan 2018 18:52

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