Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Valley-kink in Bilayer Graphene at $\nu=0$: A Charge Density Signature
  for Quantum Hall Ferromagnetism   We investigate interaction-induced valley domain walls in bilayer graphene in
the $\nu=0$ quantum Hall state, subject to a perpendicular electric field that
is antisymmetric across a line in the sample. Such a state can be realized in a
double-gated suspended sample, where the electric field changes sign across a
line in the middle. The non-interacting energy spectrum of the ground state is
characterized by a sharp domain wall between two valley-polarized regions.
Using the Hartree-Fock approximation, we find that the Coulomb interaction
opens a gap between the two lowest-lying states near the Fermi level, yielding
a smooth domain wall with a kink configuration in the valley index. Our results
suggest the possibility to visualize the domain wall via measuring the charge
density difference between the two graphene layers, which we find exhibits a
characteristic pattern. The width of the kink and the resulting pattern can be
tuned by the interplay between the magnetic field and gate electric fields.

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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
1
The categories of this paper are: cs
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: hep-lat