Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unconventional superconductivity in CuxBi2Se3   We report point contact measurements in high quality single crystals of
Cu0.2Bi2Se3. We observe three different kinds of spectra: (1)
Andreev-reflection spectra, from which we infer a superconducting gap size of
0.6mV; (2) spectra with a large gap which closes above Tc at about 10K; and (3)
tunneling-like spectra with zero-bias conductance peaks. These tunneling
spectra show a very large gap of ~2meV (2Delta/KTc ~ 14).

14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math