Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ferroelectricity and multiferroicity in anti-Ruddlesden-Popper
  structures   Combining ferroelectricity with other properties such as visible light
absorption or long-range magnetic order requires the discovery of new families
of ferroelectric materials. Here, through the analysis of a high-throughput
database of phonon band structures, we identify a new structural family of
anti-Ruddlesden-Popper phases A$_4$X$_2$O (A=Ca, Sr, Ba, Eu, X=Sb, P, As, Bi)
showing ferroelectric and anti-ferroelectric behaviors. The discovered
ferroelectrics belong to the new class of hyperferroelectrics which polarize
even under open-circuit boundary conditions. The polar distortion involves the
movement of O anions against apical A cations and is driven by geometric
effects resulting from internal chemical strains. Within this new structural
family, we show that Eu$_4$Sb$_2$O combines coupled ferromagnetic and
ferroelectric order at the same atomic site, a very rare occurrence in
materials physics.

10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat