Search

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. [ABSTRACT FROM AUTHOR]

Noble gas atoms such as Kr and Xe are byproducts of nuclear fission in nuclear plants. How to trap and confine these volatile even radioactive gases is particularly challenging. Recent studies have shown that they can be trapped in nanocages of ultrathin silica. Here, we exhibit with self-consistent phonon theory and four-phonon (4ph) scattering where the adsorption of noble gases results in an anomalous increase in lattice thermal conductivity (κL), while the presence of Cu atoms doping leads to a reduction in κL. We trace this behavior in host–guest 2D silica to an interplay of tensile strain, rattling phonon modes, and redistribution of electrons. We also find that 4ph scatterings play indispensable roles in κL of 2D silica. Our work illustrates the microscopic heat transfer mechanism in 2D silica nanocages with the immobilization of noble gas atoms and inspires further exploring materials with the kagome and glasslike κL. [ABSTRACT FROM AUTHOR]