Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of Raman G-band splitting in top-doped few-layer graphene   An experimental study of Raman scattering in N-layer graphene as a function
of the top layer doping is reported. At high doping level, achieved by a CHF_3
plasma treatment, we observe a splitting of the $G$ band in the spectra of
bilayer and 4-layer graphene (N even), whereas the splitting is not visible in
case of monolayer and trilayer graphene (N odd). The different behaviors are
related to distinct electron-phonon interactions, which are affected by
symmetry breaking and Fermi level position in different ways in the various
N-layer graphenes. In trilayer graphene, a weakening of the electron-phonon
coupling as a function of the Fermi energy induces a hardening of all
zone-center in-plane optical phonon modes, like in monolayer graphene. On the
other hand, in 4-layer graphene two distinct trends are observed in the G band
as a function of doping, suggesting the presence of two different groups of
electron-phonon interactions, like in bilayer graphene.

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The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph