Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Realizing intrinsic excitonic insulator by decoupling exciton binding
  energy from the minimum band gap   Direct-gap materials hold promises for excitonic insulator. In contrast to
indirect-gap materials, here the difficulty to distinguish from a Peierls
charge density wave is circumvented. However, direct-gap materials still suffer
from the divergence of polarizability when the band gap approaches zero,
leading to diminishing exciton binding energy. We propose that one can decouple
the exciton binding energy from the band gap in materials where band-edge
states have the same parity. First-principles calculations of two-dimensional
GaAs and experimentally mechanically exfoliated single-layer TiS 3 lend solid
supports to the new principle.

10
The categories of this paper are: q-bio
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The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
16
The categories of this paper are: stat