Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Complex evolution of the electronic structure from polycrystalline to
  monocrystalline graphene: generation of a new Dirac point   First principles calculations, employed to address the properties of
polycrystalline graphene, indicate that the electronic structure of tilt grain
boundaries in this system displays a rather complex evolution towards graphene
bulk, as the tilt angle decreases, with the generation of a new Dirac point at
the Fermi level, and an anisotropic Dirac cone of low energy excitations.
Moreover, the usual Dirac point at the {\bf K} point falls below the Fermi
level, and rises towards it as the tilt angle decreases. Further, our
calculations indicate that the grain-boundary formation energy behaves
non-monotonically with the tilt angle, due to a change in the the spatial
distribution and relative contributions of the bond-stretching and bond-bending
deformations associated with the formation of the defect.

12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn