Revisiting lattice thermal conductivity of CsCl: The crucial role of quartic anharmonicity

• Published in: Applied physics letters Vol. 124; no. 17
• Main Authors: Wang, Xiaoying, Feng, Minxuan, Xia, Yi, Sun, Jun, Ding, Xiangdong, Li, Baowen, Gao, Zhibin
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 22.04.2024
• Subjects: Anharmonicity; Cesium; Heat transfer; Phonons; Temperature dependence; Thermal conductivity; Thermal management
• DOI: 10.1063/5.0201393
• ISSN: 0003-6951

Thermal conductivity ( κ L) plays a critical role in thermal management applications. Usually, crystals with simpler structures exhibit higher κ L due to fewer phonon scatterings. However, cesium chloride (CsCl) presents an anomaly, demonstrating an unexpectedly low κ L of 1.0 W m−1 K−1 at 300 K, as observed in Professor Iversen's experimental measurement despite its simple structure. This prompts a need for understanding anomalous low κ L and matching theory with experimental observations. Our study brings forth several findings for CsCl: (i) relying solely on three-phonon scattering inadequately captures κ L. (ii) Anharmonic phonon renormalization significantly contributes to increased κ L. (iii) Coherent phonons align temperature-dependent κ L closely with the experiment. This work not only enhances understanding of anomalous κ L in CsCl but also provides an approach to bridge the gap between experiment and theory in other crystals.