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arXiv · 1809.03936

Thermal conductivity of perovskite KTaO3 and PbTiO3 from first principles

Yuhao Fu·David J. Singh
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Abstract

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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Yuhao Fu, David J. Singh. 2018-09-11. Thermal conductivity of perovskite KTaO3 and PbTiO3 from first principles. https://doi.org/10.1103/physrevmaterials.2.094408

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