Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the origin of the electronic anisotropy in iron pnicitde
  superconductors   We use polarization-resolved Raman spectroscopy to study the anisotropy of
the electronic characteristics of the iron-pnictide parent compounds
$A$Fe$_{2}$As$_{2}$ ($A$~=~Eu, Sr). We demonstrate that above the structural
phase transition at Ts the dynamical anisotropic properties of the 122
compounds are governed by the emergence of $xy$-symmetry critical collective
mode foretelling a condensation into a state with spontaneously broken
four-fold symmetry at a temperature $T^{*}$. However, the mode's critical
slowing down is intervened by a structural transition at Ts, about 80~K above
$T^{*}$, resulting in an anisotropic density wave state.

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The categories of this paper are: dg-ga
18
The categories of this paper are: econ
2
The categories of this paper are: math
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-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: bayes-an
21
The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat