Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unusual Ferroelectricity of Trans-Unitcell Ion-Displacement and
  Multiferroic Soliton in Sodium and Potassium Hydroxides   We show the first-principles evidence of a hitherto unreported type of
ferroelectricity with ultra-long ion-displacement in sodium and potassium
hydroxides. Even a small amount of proton vacancies can completely change the
mode of proton-transfer from intra-unitcell to trans-unitcell, giving rise to
multiferroic soliton with mobile magnetism and a tremendous polarization that
can be orders of magnitude higher compared with most perovskite ferroelectrics.
Their vertical polarizations of thin-film are robust against depolarizing
field, rendering various designs of 2D ferroelectric field-transistors with
non-destructive readout and ultra-high on/off ratio via sensing the switchable
metallic/insulating state.

23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph