Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal conductivity of perovskite KTaO3 and PbTiO3 from first
  principles   The low thermal conductivity of piezoelectric perovskites is a challenge for
high power transducer applications. We report first principles calculations of
the thermal conductivity of ferroelectric PbTiO$_3$ and the cubic nearly
ferroelectric perovskite KTaO$_3$. The calculated thermal conductivity of
PbTiO$_3$ is much lower than that of KTaO$_3$ in accord with experiment.
Analysis of the results shows that the reason for the low thermal conductivity
of PbTiO$_3$ is the presence of low frequency optical phonons associated with
the polar modes. These are less dispersive in PbTiO$_3$, leading to a large
three phonon scattering phase space. These differences between the two
materials are associated with the $A$-site driven ferroelectricity of PbTiO$_3$
in contrast to the $B$-site driven near ferroelectricity of KTaO$_3$. The
results are discussed in the context of modification of the thermal
conductivity of electroactive materials.

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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: math
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th