Interfacial thermal transport of carbon nanotube on substrate

Abstract

Exploring the thermal transport properties of the interface structure of low-dimensional nanomaterials contributes to a deeper understanding of the interface phonon modes and may provide theoretical support for efficient chip cooling devices. In this manuscript, we have simulated in detail the effects of system temperature, substrate location and heat flow density on the thermal transport at the SWCNT/Si interface using the Non-equilibrium Molecular Dynamics approach and predicted the interfacial thermal conductance of SWCNT/Si for second, third and fourth order phonon using the Anharmonic Inelastic model. The results show that the low-frequency acoustic branch of SWCNT is suppressed by phonon scattering from the substrate, and the low-frequency phonon branch of SWCNT is boosted by about 1 THz. The anharmonic channels and inelastic phonon scattering significantly affect the interface phonon modes at higher temperatures, and the anharmonic interactions could increase additional thermal transport channels, which result in an increased number of additional phonon peaks. The increase in temperature gradually consumes the phonons incident at the interface in SWCNT, which enhances the anharmonic scattering and weakens the nonlinear characteristics of the bimaterial heterostructure, while the weakening of the acoustic branch accompanied by the temperature increase makes the LA phonon branch thermal conduction rate slower and the interfacial thermal conductance gradually stabilizes, which leads to the weakening of the thermal rectification effect.