Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tetragonal-orthorhombic phase coexistence under magnetic fields in
  BaFe$_2$As$_2$ and Sr(Fe$_{1-x}$Co$_{x}$)$_2$As$_2$: evidence of magnetically
  driven structural transition
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an