Renormalized lattice dynamics properties from high-order phonon-phonon interactions

Accurate modeling of phonon properties is important for predictive modeling of thermal transport properties. Boltzmann transport equation (BTE) combined with first-principles computed phonon scattering rate has in recent years been used to model lattice thermal conductivity (κ_L) in bulk crystals and their alloys. The essential quantities entering BTE are phonon frequencies and lifetimes, which are regularly computed in the harmonic approximation and including only three-phonon process. In some cases, it may be necessary to include higher-order phonon-phonon interactions and temperature effects to achieve sufficient accuracy for comparison with experiments. In this talk, we will present a computational scheme to (1) efficiently correct phonon frequency shift by accounting for temperature-induced phonon renormalization and (2) include additional phonon scattering from four-phonon processes, based on high-order interatomic force constants (IFCs) extracted from compressive lattice dynamics (CSLD). We validate our method and implementation by directly comparing results to IFC-based molecular dynamics simulations. We further demonstrate the capabilities of our scheme to accurately model lattice thermal transport properties at high temperatures through a case study of NaCl and PbTe.