Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bridging Phases at the Morphotropic Boundaries of Lead-Oxide Solid
  Solutions   Ceramic solid solutions of PbZr(1-x)TixO3 (PZT) with compositions of about x=
0.50 are well-known for their extraordinarily large piezoelectric responses.
The latter are highly anisotropic, and it was recently shown that, for the
rhombohedral compositions (x< 0.5), the piezoelectric coefficients were largest
away from the polar direction, contrary to common belief. Shortly afterwards a
low-symmetry monoclinic phase was observed by synchrotron x-ray diffraction at
around x=0.50. Similar behavior and features are also present in a number of
related lead-based strongly-piezoelectric single crystals, such as PMN-PT,
PZN-PT, and PSN-PT, with piezoelectric coeficients of about 2500 pm/V, the
highest values recorded to date. Recent experimental and theoretical work has
greatly improved our understanding of these technologically-important systems,
but there are still some open questions. In this review we try to summarize the
most recent progress in the field.

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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an
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The categories of this paper are: stat
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: math
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The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph