Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Phase-field modeling and electronic structural analysis of flexoelectric
  effect at 180{\deg} domain walls in ferroelectric PbTiO3
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
3
The categories of this paper are: physics