Tutorial: Concepts and numerical techniques for modeling individual phonon transmission at interfaces

TL;DR

This tutorial introduces an extended Atomistic Green's Function method based on the Bloch matrix to model and analyze individual phonon mode transmission at interfaces, providing detailed insights into nanoscale thermal transport.

Contribution

It presents a novel extension of the AGF method to explicitly model and analyze individual phonon modes and their transmission characteristics at interfaces.

Findings

The method reveals wavelength and polarization dependence of phonon transmission.

Application to carbon nanotube junctions demonstrates detailed modal insights.

Establishes relationship between phonon transmission coefficient and dispersion.

Abstract

At the nanoscale, thermal transport across the interface between two lattice insulators can be described by the transmission of bulk phonons and depends on the crystallographic structure of the interface and the bulk crystal lattice. In this tutorial, we give an account of how an extension of the Atomistic Green's Function (AGF) method based on the concept of the Bloch matrix can be used to model the transmission of individual phonon modes and allow us to determine the wavelength and polarization dependence of the phonon transmission. Within this framework, we can explicitly establish the relationship between the phonon transmission coefficient and dispersion. Details of the numerical methods used in the extended AGF method are provided. To illustrate how the extended AGF method can be applied to yield insights into individual phonon transmission, we study the (16,0)/(8,0) carbon nanotube intramolecular junction. The method presented here sheds light on the modal contribution to interfacial thermal transport between solids.