Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-Step Modification of Phonon Mean Free Paths for Thermal Conductivity
  Predictions of Thin-Film-Based Nanostructures   As one simple metamaterial, nanopatterns are often fabricated across a thin
film so that the thermal transport can be manipulated. The etched sidewalls for
these nanostructures are usually rough due to surface defects introduced during
the nanofabrication, whereas the top and bottom film surfaces are smoother. In
existing analytical models, the contrast between these surfaces has not been
addressed and all boundaries are assumed to be diffusive for phonon reflection.
In this paper, a new two-step approach to address this issue is proposed for
phonon transport modeling of general thin-film-based structures. In this
approach, the effective in-plane phonon mean free paths ({\Lambda}_Film) are
first modified from the bulk phonon MFPs to account for the influence of the
top/bottom film surfaces, with possibly enhanced probability of specular phonon
reflection at cryogenic temperatures. This {\Lambda}_Film is further modified
to include the scattering by etched sidewalls with almost completely diffusive
phonon scattering. Such a two-step phonon mean free path modification yields
almost identical results as frequency-dependent phonon Monte Carlo simulations
for etched nanowires and representative nanoporous thin films. This simple yet
accurate analytical model can be applied to general thin-film-based
nanostructures to combine the phonon size effects along orthogonal directions.

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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci