Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superconducting Fluctuations and Anomalous Phonon Renormalization much
  above superconducting transition temperature in Ca4Al2O5.7Fe2As2   Raman studies on Ca4Al2O5.7Fe2As2 superconductor in the temperature range of
5 K to 300 K, covering the superconducting transition temperature Tc ~ 28.3 K,
reveal that the Raman mode at ~ 230 cm-1 shows a sharp jump in frequency by ~ 2
% and linewidth increases by ~ 175 % at To ~ 60 K. Below To, anomalous
softening of the mode frequency and a large decrease by ~ 10 cm-1 in the
linewidth is observed. These precursor effects at T0 (~ 2Tc) are attributed to
significant superconducting fluctuations, possibly enhanced due to reduced
dimensionality arising from weaked coupling between the well separated (~ 15
{\AA}) Fe-As layers in the unit cell. A large blue-shift of the mode frequency
between 300 K to 60 K (~7%) indicates strong spin-phonon coupling in this
superconductor.

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The categories of this paper are: solv-int
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The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
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The categories of this paper are: eess
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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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: bayes-an
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The categories of this paper are: stat