Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Epitaxial growth and transport properties of Nb-doped SrTiO$_{3}$ thin
  films   Nb-doped SrTiO$_{3}$ epitaxial thin films have been prepared on (001)
SrTiO$_{3}$ substrates using pulsed laser deposition. A high substrate
temperature ($>1000^{\circ}{C}$) was found to be necessary to achieve
2-dimensional growth. Atomic force microscopy reveals atomically flat surfaces
with 3.9 \AA $ $ steps. The films show a metallic behavior, residual
resistivity ratios between 10 and 100, and low residual resistivity of the
order of 10$^{-4}$$\Omega$cm. At 0.3 K, a sharp superconducting transition,
reaching zero resistance, is observed.

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The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom