Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Far-infrared signature of the superconducting gap in intercalated
  graphite CaC6   Terahertz reflectance spectra of the Ca-intercalated graphite CaC6 reveal a
superconducting gap below 11K. The gap signature lacks a sharp onset to full
reflectivity at 2Delta, but rather shows a distribution of gap values
consistent with an anisotropic gap. The experimental data were successfully
fitted to the gap distribution obtained from density functional calculations by
Sanna et al. (Phys.Rev. B75, 020511, 2007). The temperature dependence of the
superconducting gap is characteristic for a BCS type superconductor.

22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
3
The categories of this paper are: physics