Violation of the T ^-1 Relationship in the Lattice Thermal Conductivity of Mg₃Sb₂ with Locally Asymmetric Vibrations.

ABSTRACT: Most crystalline materials follow the guidelines of T ^-1 temperature-dependent lattice thermal conductivity (κ _L ) at elevated temperatures. Here, we observe a weak temperature dependence of κ _L in Mg₃Sb₂, T ^-0.48 from theory and T ^-0.57 from measurements, based on a comprehensive study combining ab initio molecular dynamics calculations and experimental measurements on single crystal Mg₃Sb₂. These results can be understood in terms of the so-called "phonon renormalization" effects due to the strong temperature dependence of the interatomic force constants (IFCs). The increasing temperature leads to the frequency upshifting for those low

SUBMITTER: Zhu Y 

PROVIDER: S-EPMC7877392 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature