Temperature-dependent thermal transport of single molecular junctions from semi-classical Langevin molecular dynamics

TL;DR

This study uses semiclassical Langevin molecular dynamics to analyze how quantum statistics and anharmonic interactions influence thermal transport in single-molecular junctions across a wide temperature range, aiding the development of molecular devices.

Contribution

It introduces a comprehensive theoretical framework that includes both quantum statistics and anharmonic interactions to understand thermal transport in single-molecular junctions over various temperatures.

Findings

Quantum statistics are crucial for graphene junctions at room temperature.

Anharmonic interactions are negligible in graphene junctions.

Different roles of quantum and anharmonic effects in Au and graphene junctions.

Abstract

Thermal conductance of single molecular junctions at room temperature has been measured recently using picowatt-resolution scanning probes. However, fully understanding thermal transport in a much wider temperature range is needed for the exploration of energy transfer at single-molecular limit and the development of single-molecular devices. Here, employing a semiclassical Langevin molecular dynamics method, a comparative study is performed on the thermal transport of an alkane chain between Au and graphene electrodes, respectively. We illustrate the different roles of quantum statistics and anharmonic interaction in the two types of junctions. For a graphene junction, quantum statistics is essential at room temperature, while the anharmonic interaction is negligible. For a Au junction, it is the other way. Our study paves the way for theoretically understanding thermal transport of realistic single-molecular junctions in the full temperature range by including both quantum statistics and anharmonic interaction within one theoretical framework.