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arXiv · 1510.05422

A first-principles study on the phonon transport in layered BiCuOSe

Hezhu Shao·Xiaojian Tan·Guo-Qiang Liu·Jun Jiang·Haochuan Jiang
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Abstract

First-principles calculations are employed to investigate the phonon transport of BiCuOSe. Our calculations reproduce the lattice thermal conductivity of BiCuOSe. The calculated gruneisen parameter is 2.4~2.6 at room temperature, a fairly large value indicating a strong anharmonicity in BiCuOSe, which leads to its ultralow lattice thermal conductivity. The contribution to total thermal conductivity from high-frequency optical phonons, which are mostly contributed by the vibrations of O atoms, is larger than 1/3, remarkably different from the usual picture with very little contribution from high-frequency optical phonons. Our calculations show that both the high group velocities and low scattering processes involved make the high-frequency optical modes contribute considerably to the total lattice thermal conductivity. In addition, we show that the sound velocity and bulk modulus along $a$ and $c$ axes exhibit strong anisotropy, which results in the anisotropic thermal conductivity in BiCuOSe.

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Hezhu Shao, Xiaojian Tan, Guo-Qiang Liu, Jun Jiang, Haochuan Jiang. 2015-10-19. A first-principles study on the phonon transport in layered BiCuOSe. https://doi.org/10.1038/srep21035

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