Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Double-resonant LA phonon scattering in defective graphene and carbon
  nanotubes   We present measurements of the $D''$ Raman mode in graphene and carbon
nanotubes at different laser excitation energies. The Raman mode around 1050 -
1150\,cm$^{-1}$ originates from a double-resonant scattering process of
longitudinal acoustic (LA) phonons with defects. We investigate its dependence
on laser excitation energy, on the number of graphene layers and on the carbon
nanotube diameter. We assign this Raman mode to so-called 'inner' processes
with resonant phonons mainly from the $\Gamma-K$ high-symmetry direction. The
asymmetry of the $D''$ mode is explained by additional contributions from
phonons next to the $\Gamma-K$ line. Our results demonstrate the importance of
inner contributions in the double-resonance scattering process and add a fast
method to investigate acoustic phonons in graphene and carbon nanotubes by
optical spectroscopy.

25
The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
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The categories of this paper are: cmp-lg
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn