Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Phase diagram and physical properties of NaFe$_{1-x}$Cu$_x$As single
  crystals
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph