Nonequilibrium Green's function method for thermal transport in junctions

TL;DR

This paper develops a detailed nonequilibrium Green's function approach for analyzing thermal transport in nanostructures, incorporating nonlinear effects and mean-field theory, with applications to various atomic systems.

Contribution

It introduces a comprehensive Green's function framework for thermal transport that includes nonlinear effects and proposes a self-consistent mean-field approach.

Findings

Nonlinearity suppresses thermal transport at moderate temperatures.

The method is successfully applied to diverse nanostructures.

Mean-field calculations align with molecular dynamics simulations.

Abstract

We present a detailed treatment of the nonequilibrium Green's function method for thermal transport due to atomic vibrations in nanostructures. Some of the key equations, such as self-energy and conductance with nonlinear effect, are derived. A self-consistent mean-field theory is proposed. Computational procedures are discussed. The method is applied to a number of systems including one-dimensional chains, a benzene ring junction, and carbon nanotubes. Mean-field calculations of the Fermi-Pasta-Ulam model are compared with classical molecular dynamics simulations. We find that nonlinearity suppresses thermal transport even at moderately high temperatures.