Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dramatic increase of the onset critical temperature and critical field
  of elemental Sn in the form of thin nanowires   Sn is a well-known classical superconductor on the border between type I and
type II with critical temperature of 3.722K and critical field of 0.031T. We
show by means of specific heat and electric magneto-transport data that its
critical parameters can be dramatically increased if it is brought in the form
of loosely bound bundles of thin nanowires. The specific heat displays a
pronounced double phase transition at 3.7K and 5.5K, which we attribute to the
inner 'bulk' contribution of the nanowires and to the surface contribution,
respectively. The latter is visible only because of the large volume fraction
of the surface layer in relation to their bulk inner volume. The upper
transition coincides with the onset of the resistive transition, while zero
resistance is gradually approached below the lower transition. The large
coherence length of 230nm at 0K likely actuates a Josephson coupling between
adjacent neighboring nanowires and thus suppresses the effect of 1D phase
fluctuations along the nanowires, and stabilizes 3D phase coherence throughout
the entire network with zero resistance. A magnetic field of more than 3T is
required to restore the normal state, which means that the critical field is
enhanced by about two orders of magnitude with respect to Sn in its bulk form.

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The categories of this paper are: mtrl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
1
The categories of this paper are: cs
3
The categories of this paper are: physics
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The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
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The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga