Impacts of Atomistic Coating on Thermal Conductivity of Germanium Nanowires

TL;DR

This study uses molecular dynamics simulations to show that atomistic coating can significantly reduce the thermal conductivity of germanium nanowires, with implications for thermal management in nanodevices.

Contribution

It reveals how atomistic coating and interface roughness influence thermal conductivity and identifies a critical coating thickness for optimizing heat transfer.

Findings

Thermal conductivity can be reduced by over 25% with coating.

A critical coating thickness exists where conductivity surpasses that of uncoated nanowires.

Interface roughness further decreases thermal conductivity.

Abstract

By using non-equilibrium molecular dynamics simulations, we demonstrated that thermal conductivity of Germanium nanowires can be reduced more than 25% at room temperature by atomistic coating. There is a critical coating thickness beyond which thermal conductivity of the coated nanowire is larger than that of the host nanowire. The diameter dependent critical coating thickness and minimum thermal conductivity are explored. Moreover, we found that interface roughness can induce further reduction of thermal conductivity in coated nanowires. From the vibrational eigen-mode analysis, it is found that coating induces localization for low frequency phonons, while interface roughness localizes the high frequency phonons. Our results provide an available approach to tune thermal conductivity of nanowires by atomic layer coating.