Thermal conductivity spectrum calculation from first-principles-based harmonic phonon theory

TL;DR

This paper introduces an empirical model that predicts the thermal conductivity spectrum of crystals using only harmonic phonon properties and bulk thermal conductivity, simplifying the computational process for material screening.

Contribution

The paper presents a novel empirical model that accurately reproduces thermal conductivity spectra from first-principles harmonic phonon data, reducing computational complexity.

Findings

Model accurately reproduces spectra for various crystals.

Simplifies thermal conductivity calculations without anharmonic computations.

Facilitates faster material screening for nanostructured thermal management.

Abstract

In recent years, nanostructuring of dielectric and semiconducting crystals has enhanced controllability of their thermal conductivity. To carry out computational material search for nanostructured materials with desirable thermal conductivity, a key property is the thermal conductivity spectrum of the original single crystal, which determines the appropriate length scale of nanostructures and mutual adaptability of different kinds of nanostructures. Although the first-principles phonon transport calculations have become accessible, the anharmonic lattice dynamics calculations are still heavy to scan many materials. To this end, we have developed an empirical model that describes the thermal conductivity spectrum in terms only of harmonic phonon properties and bulk thermal conductivity. The model was tested for several crystals with different structures and thermal conductivities, and was confirmed to reproduce the overall profiles of thermal conductivity spectra and their anharmonic calculations.