Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nodeless superconductivity in Ca3Ir4Sn13: evidence from quasiparticle
  heat transport   We report resistivity $\rho$ and thermal conductivity $\kappa$ measurements
on Ca$_3$Ir$_4$Sn$_{13}$ single crystals, in which superconductivity with $T_c
\approx 7$ K was claimed to coexist with ferromagnetic spin-fluctuations. Among
three crystals, only one crystal shows a small hump in resistivity near 20 K,
which was previously attributed to the ferromagnetic spin-fluctuations. Other
two crystals show the $\rho \sim T^2$ Fermi-liquid behavior at low temperature.
For both single crystals with and without the resistivity anomaly, the residual
linear term $\kappa_0/T$ is negligible in zero magnetic field. In low fields,
$\kappa_0(H)/T$ shows a slow field dependence. These results demonstrate that
the superconducting gap of Ca$_3$Ir$_4$Sn$_{13}$ is nodeless, thus rule out
nodal gap caused by ferromagnetic spin-fluctuations.

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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
1
The categories of this paper are: cs
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The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
10
The categories of this paper are: q-bio