Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Revisiting the Reduction of Thermal Conductivity in Nano- to
  Micro-Grained Bismuth Telluride: The Importance of Grain-Boundary Thermal
  Resistance   Nanograined bulk alloys based on bismuth telluride (Bi2Te3) are the dominant
materials for room-temperature thermoelectric applications. In numerous
studies, existing bulk phonon mean free path (MFP) spectra predicted by
atomistic simulations suggest sub-100 nm grain sizes are necessary to reduce
the lattice thermal conductivity by decreasing phonon MFPs. This is in contrast
with available experimental data, where a remarkable thermal conductivity
reduction is observed even for micro-grained Bi2Te3 samples. In this work,
first-principles phonon MFPs along both the in-plane and cross-plane directions
are re-computed for bulk Bi2Te3. These phonon MFPs can explain new and existing
experimental data on flake-like Bi2Te3 nanostructures with various thicknesses.
For polycrystalline Bi2Te3-based materials, a better explanation of the
experimental data requires further consideration of the grain-boundary thermal
resistance that can largely suppress the transport of high-frequency optical
phonons.

18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas