Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interplay of epitaxial strain and rotations in PbTiO$_3$/PbZrO$_3$
  superlattices from first principles   We present first-principles calculations of the structural phase behavior of
the [1:1] \pzta\ superlattice and the \ptoa\ and \pzoa\ parent compounds as a
function of in-plane epitaxial strain. A symmetry analysis is used to identify
the phases and clarify how they arise from an interplay between different kinds
of structural distortions, including out-of-plane and in-plane polar modes,
rotation of oxygen octahedra around out-of-plane or in-plane axes, and an
anti-polar mode. Symmetry-allowed intermode couplings are identified and used
to elucidate the nature of the observed phase transitions. For the
minimum-period [1:1] \pzta\ superlattice, we identify a sequence of three
transitions that occur as the in-plane lattice constant is increased. All four
of the phases involve substantial oxygen octahedral rotations, and an antipolar
distortion is important in the high-tensile-strain phase. Inclusion of these
distortions is found to be crucial for an accurate determination of the phase
boundaries.

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The categories of this paper are: eess
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: astro-ph
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The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an