Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Local density of states in the superconductor
  $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br   Low temperature scanning tunneling spectroscopy reveals the local density of
states of the organic superconductor $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br,
that was cut in-situ in ultra-high vacuum perpendicular to the superconducting
BEDT-TTF layers. The spectra confirm that superconductivity is confined to the
conducting BEDT-TTF layers, while the Cu[N(CN)$_2$]Br anion layers are
insulating. The density of states comprises a twofold superconducting gap,
which is attributed to the two separated bands crossing the Fermi surface.

1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ