Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Raman Signal Reveals the Rhombohedral Crystallographic Structure in
  Ultra-thin Layers of Bismuth Thermally Evaporated on Amorphous Substrate
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys