Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mapping electronic states of dual-parallel and symmetric zigzag grain
  boundaries of graphene on highly oriented pyrolytic graphite   The grain boundaries (GBs) of a graphene surface were extensively studied
because GBs with specific defect configurations result in the formation of new
curved structures, which can be treated as new carbon allotropes. We studied
the structures and electronic spectra of two periodic GBs in graphene on highly
oriented pyrolytic graphite (HOPG) surfaces using scanning tunneling microscopy
and spectroscopy (STM/S). Our results demonstrated that a GB consisting of dual
parallel periodic dislocation cores of pentagonal-heptagonal (5-7) carbon rings
gives rise to an enhanced localized state at 0.45 eV above the Dirac point in
graphene surfaces, which is attributed to van Hove singularities (VHSs).
Moreover, the energy positions of the localized states are varied between 0.40
and 0.47 eV depending on the site and eventually decayed to 0.36 eV. The
variation of the energy positions is induced by two parallel GBs because of the
higher electron density at the GB as a defect center and the lower electron
away from the GB. Another periodic GB with a symmetric zigzag structural
feature induced VHSs at -0.038 and 0.12 eV near the Fermi level. Moreover,
intervalley scattering was observed on both these GBs. This means that carrier
concentration and thus, the conductance around the periodic GBs can be
significantly enhanced by localized density of states. This finding suggests
that graphene with a properly embedded ordered GB is promising for improving
the performance of graphene-based electronic devices.

23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex