Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Impurity Scattering Effect on Superconductivity and the Violation of
  Anderson Theorem in Ba(Fe_{1-x}Co_x)_2As_2 Single Crystals   Low-temperature specific heat (SH) and resistivity were measured on
Ba(Fe_{1-x}Co_x)_2As_2 single crystals in wide doping region. A sizeable
residual specific heat coefficient \gamma_0 was observed in the low temperature
limit of all samples. The specific heat jump near T_c, i.e. \Delta C/T|_{T_c}
and the upper critical field H_{c2}^c (H||c) were also determined. It is found
that -\gamma_0, \Delta C/T|_{T_c}, \sqrt{H_{c2}^c} and T_c all shared a similar
evolution with doping. All these can be well understood within the model of
S$^\pm$ pairing symmetry when accounting the Co-dopants as unitary scattering
centers in the FeAs planes. Our results give a direct evidence for the
violation of the Anderson theorem in FeAs-based superconductors.

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The categories of this paper are: stat
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: patt-sol