Thermal conduction in nanoscale systems

Abstract

Thermal transportation in nanoscale systems has attracted a lot of interest in recent years due to the progress in nanotechnology. Compared with macroscale systems, nanoscale systems present many new challenges due to their dimensional restrictions. In this thesis, the nanoscale thermal transport was studied using both classical and quantum mechanical methods. Specifically, molecular dynamics method was used to calculate the thermal conductivity of a one-dimensional chain model and a tension dependence of the conductivity was discovered. The non-equilibrium Green's function method was derived using equation of motion method and Keldysh formalism. It was then applied to calculate the thermal conductance of systems at relatively low temperatures. Thermal rectification effect in a one-dimensional asymmetrical chain was studied and it was found that high frequency phonons are the major contributors for the thermal rectification effect.