Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superconducting properties of Cu intercalated Bi$_2$Se$_3$ studied by
  Muon Spin Spectroscopy   We present muon spin rotation measurements on superconducting Cu intercalated
Bi$_2$Se$_3$, which was suggested as a realization of a topological
superconductor. We observe a clear evidence of the superconducting transition
below 4 K, where the width of magnetic field distribution increases as the
temperature is decreased. The measured broadening at mK temperatures suggests a
large London penetration depth in the $ab$ plane ($\lambda_{\mathrm{eff}}\sim
1.6$ $\mathrm{\mu}$m). We show that the temperature dependence of this
broadening follows the BCS prediction, but could be consistent with several gap
symmetries.

23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio