Dislocation-Limited Thermal Conductivity in LiF: Revisiting Perturbative Models

Abstract

We revisit models to describe phonon–dislocation interactions and resulting dislocation-limited thermal conductivity (k), particularly as applied to describe the temperature-dependent k behavior of LiF with significant dislocation densities. Coupling semiempirical models of phonon scattering from dislocation strain fields provided by Klemens and Carruthers with density functional theory description of the phonons and input parameters, we find that both models significantly overpredict the measured k of LiF, as found previously. However, more direct application of the quantum perturbation theory description, from which the models were derived, gives significantly stronger phonon–dislocation scattering and strongly underpredicts the measured k data. We revisit the derivation of phonon–dislocation–strain field scattering and provide numerical details regarding its implementation. This work demonstrates that quantum perturbative calculations, now accessible to modern computational architectures, may provide a reasonable description of dislocation-limited k in materials as governed by phonon–strain field interactions provided that questions regarding the relevant strain field range can be resolved.