Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Possible excited spin density wave states in zigzag graphene nanoribbons   We theoretically examine the possible spin ordered states in zigzag graphene
nanoribbon in a large supercell by the self-consistent mean field method as
well as the first principle calculation. In addition to the well-known
anti-ferromagnetic (AF) and ferromagnetic (FM) edge states, we find that there
are also some excited spin density wave (ESDW) states, the energy of which are
close to the AF edge state (ground state). We thus argue that these ESDW states
may coexist in experiment when the temperature is not too low. Our numerical
results indicate that the allowed ESDW are commensurate; and their dispersion
curve is plotted. This interesting feature results from the fact the there is a
flat edge band near the Fermi surface in the graphene zigzag ribbon. Finally we
use the non-equilibrium Green function theory combined with the Hubbard model
to calculate some possible spin polarization states localized in the middle and
terminal parts of graphene nanoribbons.

31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas