Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First-principles Study on Piezoelectricity and Spontaneous Polarization
  in Bi(Fe,Co)O3   Solid solution BiFe1-xCoxO3 shows anti-ferromagnetic order and pyroelectric
order, simultaneously. It has been known that BiFe1-xCoxO3 exhibits a
structural phase transition between monoclinic and tetragonal phases as x
increases. This kinds of transition is often called morphotoropic phase
boundary, which is well known to take place in a representative piezoelectric
oxide, PbZr1-xTixO3. In order to theoretically understand the piezoelectric
property in BiFe1-xCoxO3, we performed ab-initio electronic-structure
calculations and studied the structural stability, the magnetic property, and
the electronic polarization by means of super-cell approach. It turns out that
the large electric polarization and the particular pyramidal coordination
suppress the response of the electric polarization under strain. A way to
enhance the piezoelectric effect in BiFe1-xCoxO3 is proposed.

9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs