Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Valley-Polarized Metals and Quantum Anomalous Hall Effect in Silicene   Silicene is a monolayer of silicon atoms forming a two-dimensional honeycomb
lattice, which shares almost every remarkable property with graphene. The low
energy structure of silicene is described by Dirac electrons with relatively
large spin-orbit interactions due to its buckled structure. The key observation
is that the band structure is controllable by applying the electric field to a
silicene sheet. We explore the phase diagram of silicene together with exchange
field $M$ and by applying electric field $E_{z}$. There appear quantum
anomalous Hall (QAH) insulator, valley polarized metal (VPM), marginal valley
polarized metal (M-VPM), quantum spin Hall (QSH) insulator and band insulator
(BI). They are characterized by the Chern numbers and/or by the edge modes of a
nanoribbon. It is intriguing that electrons have been moved from a conduction
band at the K point to a valence band at the K' point for $E_{z}>0$ in the VPM.
We find in the QAH phase that flat gapless edge modes emerge and that spins
form a momentum-space skyrmion to yield the Chern number. It is remarkable that
a topological quantum phase transition can be induced simply by changing
electric field in a single silicene sheet.

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The categories of this paper are: nucl-ex
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
2
The categories of this paper are: math
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph