Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase transitions, stability, and dielectric response of the domain
  structure in ferroelectric-ferroelastic thin films   We present the first analytical study of phase transitions in
ferroelastic-ferroelectric epitaxial thin films on exactly solvable model. The
emerging domain structure with domains of equal width (which may be
exponentially large on a "soft" substrate) always remains stable irrespective
of the film thickness. The dielectric response of an epitaxial film is {\em
smaller} than that of a free film, in striking contrast with assertions in the
literature.

6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph