Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First-principles calculations of the electronic, optical and elastic
  properties of CdIn2S4 spinel at the ambient and elevated pressure   CdIn2S4 thiospinel was studied by means of the first principles calculations
in both generalized gradient and local density approximations (GGA and LDA).
The structural, electronic, optical and elastic properties were calculated in
the pressure range from 0 to 10 GPa, below the pressure of phase transition for
this compound. One of the main results of the paper is that the previously
encountered in the literature controversy regarding the character of the
CdIn2S4 band gap was resolved in favor of the indirect gap. Pressure
coefficient of the band gap estimated as 0.071/0.063 eV/GPa (GGA/LDA) is in
excellent agreement with the found in the literature experimental data of 0.076
or 0.069 eV/GPa. Calculated pressure dependence of the unit cell volume follows
the experimental results very closely. Dependence of the interionic distances,
lattice parameter and all elastic constants on pressure was calculated. Refined
estimations of the Debye temperature for CdIn2S4 are given as 280 K (LDA) and
252 K (GGA). Elastic anisotropy of CdIn2S4 was visualized by plotting
three-dimensional dependence of the Young modulus on a direction in the crystal
lattice; it was established that the lowest Young moduli values are realized if
the external stress is applied along the crystallographic axes.

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The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
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The categories of this paper are: eess