Validating First-Principles Phonon Lifetimes via Inelastic Neutron Scattering

Abstract

Phonon lifetimes are a key component of quasiparticle theories of transport, yet first-principles lifetimes are rarely directly compared to inelastic neutron scattering (INS) results. Existing comparisons show discrepancies even at temperatures where perturbation theory is expected to be reliable. In this work, we demonstrate that the reciprocal space voxel ($q$-voxel), which is the finite region in reciprocal space required in INS data analysis, must be explicitly accounted for within theory in order to draw a meaningful comparison. We demonstrate accurate predictions of peak widths of the scattering function when accounting for the $q$-voxel in CaF${}_2$ and ThO${}_2$. Passing this test implies high fidelity of the phonon interactions and the approximations used to compute the Green's function, serving as critical benchmark of theory, and indicating that other material properties should be accurately predicted; which we demonstrate for thermal conductivity.

References in corpus (2)

• Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\mu SR$ Experiments
• A group theoretical approach to computing phonons and their interactions

Cited by in corpus (5)

• Phonon thermal transport in UO${}_2$ via self-consistent perturbation theory
• Anharmonic phonon behavior via irreducible derivatives: self-consistent perturbation theory and molecular dynamics
• Comparing first-principles density functionals plus corrections for the lattice dynamics of YBa${}_2$Cu${}_3$O${}_6$
• Implications of phonon anisotropy on thermal conductivity of fluorite oxides
• Parameterizing empirical interatomic potentials for predicting thermophysical properties via an irreducible derivative approach: the case of ThO${}_2$ and UO${}_2$