Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Built-in Electric-Field-Control of Magnetic Coupling in van der Waals
  semiconductors
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an