A scattering rate model for accelerated evaluation of lattice thermal conductivity bypassing anharmonic force constants

Abstract

Predicting the lattice thermal conductivity from the atomic structure is important to many scientific and engineering applications. However, the state-of-the-art method based on first-principles calculations of the three-phonon scattering process is bound with high computational cost, while semiempirical models such as the Slack equation are less accurate. In this work, we examined the theoretical background of the commonly used computational models for thermal conductivity evaluation and proposed an improved quasiharmonic model based on an early approximation for three-phonon scattering strength. This model has significantly reduced computational cost as compared to the full anharmonic lattice dynamics calculations but retains a fairly good quantitative accuracy comparing to many semiempirical models. It also allows one to include normal processes in phonon-phonon scattering and obtain the phonon relaxation times.