Importance of Four-Phonon Scattering at High Temperatures or for Strongly Anharmonic Materials
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2015-10-02 |
| Journal | arXiv (Cornell University) |
| Authors | Tianli Feng, Xiulin Ruan |
Abstract
Section titled āAbstractāRecently, first principle-based prediction of lattice thermal conductivity $\kappa$ from the perturbation theory has achieved significant success. However, it only includes three-phonon scattering due to the assumption that four-phonon and higher-order processes are generally unimportant. Also, directly evaluating the scattering rates of four-phonon and higher-order processes has been a long-standing challenge. In this work, however, we have developed a formalism to explicitly determine quantum mechanical scattering probability matrices for four-phonon scattering in the full Brillouin Zone, and by mitigating the computational challenge we have directly calculated four-phonon scattering rates. We find that four-phonon scattering rates are comparable to three-phonon scattering rates at medium and high temperatures, and they increase quadratically with temperature. As a consequence, $\kappa$ of Lennard-Jones argon is reduced by more than 60% at 80 K when four-phonon scattering is included. Also, in less anharmonic materials ā diamond, silicon, and germanium, $\kappa$ is still reduced considerably at high temperature by four-phonon scattering. Also, the thermal conductivity of optical phonons is dominated by the fourth and higher orders phonon scattering even at low temperature.
Tech Support
Section titled āTech SupportāOriginal Source
Section titled āOriginal Sourceā- DOI: None