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arXiv · 2306.06847

The role of high-order anharmonicity and off-diagonal terms in thermal conductivity: a case study of multi-phase CsPbBr3

Xiaoying Wang·Zhibin Gao·Guimei Zhu·Jie Ren·Lei Hu·Jun Sun·Xiangdong Ding·Yi Xia·Baowen Li
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Abstract

We investigate the influence of three- and four-phonon scattering, perturbative anharmonic phonon renormalization, and off-diagonal terms of coherent phonons on the thermal conductivity of CsPbBr3 phase change perovskite, by using advanced implementations and first-principles simulations. Our study spans a wide temperature range covering the entire structural spectrum. Notably, we demonstrate that the interactions between acoustic and optical phonons result in contrasting trends of phonon frequency shifts for the high-lying optical phonons in orthorhombic and cubic CsPbBr3 as temperature varies. Our findings highlight the significance of wave-like tunneling of coherent phonons in ultralow and glass-like thermal conductivity in halide perovskites.

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Xiaoying Wang, Zhibin Gao, Guimei Zhu, Jie Ren, Lei Hu, Jun Sun, Xiangdong Ding, Yi Xia, Baowen Li. 2023-06-12. The role of high-order anharmonicity and off-diagonal terms in thermal conductivity: a case study of multi-phase CsPbBr3. https://doi.org/10.1103/physrevb.107.214308

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