Using Green-Kubo modal analysis (GKMA) and interface conductance modal analysis (ICMA) to study phonon transport with molecular dynamics

Abstract

While current descriptions of thermal transport exist for well-ordered solids, i.e., crystal lattices, new methods are needed to describe thermal transport in systems with lack of symmetry such as structurally/compositionally disordered solids and interfaces. In this tutorial, we discuss the formalism, implementation, and application of two recently developed methods, Green-Kubo modal analysis and interface conductance modal analysis, to predict the thermal conductivity and thermal interface conductance, respectively. Specifically, these methods enable the prediction of phonon contributions to transport in crystalline materials with any level of defects, up through fully amorphous solids, dilute to fully random alloys, molecules, nanostructures, and across interfaces involving any of these material classes - all within a single and unified perspective. This tutorial article not only describes the methods, but also provides example codes that can be used for their direct implementation. The design and functionality of the codes is also discussed in order to reduce the barrier to more extensive utilization of these approaches by others.