Transition from near-field thermal radiation to phonon heat conduction at sub-nanometre gaps
Name
Bridging Conduction and Radiation Dspace (November 8 2015).pdf
Description
Main article
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4.24 MB
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Author(s)
Chiloyan, Vazrik
Garg, Jivtesh
Esfarjani, Keivan
Chen, Gang
Date Issued
April 2015
Journal
Nature Communications
Publisher
Nature Publishing Group
Citation
Chiloyan, Vazrik, Jivtesh Garg, Keivan Esfarjani, and Gang Chen. “Transition from Near-Field Thermal Radiation to Phonon Heat Conduction at Sub-Nanometre Gaps.” Nat Comms 6 (April 7, 2015): 6755.
Version
Author's final manuscript
Abstract
When the separation of two surfaces approaches sub-nanometre scale, the boundary between the two most fundamental heat transfer modes, heat conduction by phonons and radiation by photons, is blurred. Here we develop an atomistic framework based on microscopic Maxwell’s equations and lattice dynamics to describe the convergence of these heat transfer modes and the transition from one to the other. For gaps >1 nm, the predicted conductance values are in excellent agreement with the continuum theory of fluctuating electrodynamics. However, for sub-nanometre gaps we find the conductance is enhanced up to four times compared with the continuum approach, while avoiding its prediction of divergent conductance at contact. Furthermore, low-frequency acoustic phonons tunnel through the vacuum gap by coupling to evanescent electric fields, providing additional channels for energy transfer and leading to the observed enhancement. When the two surfaces are in or near contact, acoustic phonons become dominant heat carriers.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1038/ncomms7755
