Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural and electronic properties of
  $\alpha,\beta$-(BEDT-TTF)$_2$I$_3$ and $\kappa$-(BEDT-TTF)$_2$X$_3$
  (X=I,F,Br,Cl) organic charge transfer salts   (BEDT-TFF)$_2$I$_3$ charge transfer salts are reported to show
superconductivity and pressure induced quasi two-dimensional Dirac cones at the
Fermi level. By performing state of the art ab initio calculations in the
framework of density functional theory, we investigate the structural and
electronic properties of the three structural phases $\alpha$, $\beta$ and
$\kappa$. \edit{We furthermore report about the irreducible representations of
the corresponding electronic band structures, symmetry of their crystal
structure, and discuss the origin of band crossings. Additionally, we discuss
the chemically induced strain in $\kappa$-(BEDT-TTF)$_2$I$_3$ achieved by
replacing the Iodine layer with other Halogens: Fluorine, Bromine and Chlorine.
In the case of $\kappa$-(BEDT-TTF)$_2$F$_3$, we identify topologically
protected crossings within the band structure. These crossings are forced to
occur due to the non-symmorphic nature of the crystal.} The calculated
electronic structures presented here are added to the organic materials
database (OMDB).

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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
31
The categories of this paper are: ao-sci