Thermal transport in silicene nanotubes: Effects of length, grain boundary and strain

TL;DR

This study uses molecular dynamics simulations to analyze how length, grain boundaries, defects, strain, and temperature influence the thermal conductivity of silicene nanotubes, revealing key factors affecting heat transport in these nanostructures.

Contribution

It provides new insights into the effects of structural defects, strain, and temperature on the thermal conductivity of silicene nanotubes, with detailed mechanistic analysis.

Findings

Thermal conductivity varies with length but is insensitive to diameter and chirality.

Grain boundaries reduce thermal conductivity by about 30%.

Thermal conductivity increases with tensile strain up to a maximum before decreasing.

Abstract

Thermal transport behavior in silicene nanotubes has become more important due to the application of these promising nanostructures in the engineering of next-generation nanoelectronic devices. We apply non-equilibrium molecular dynamics (NEMD) simulations to study the thermal conductivity of silicene nanotubes with different lengths and diameters. We further explore the effects of grain boundary, strain, vacancy defect, and temperature in the range of 300-700 K on the thermal conductivity. Our results indicate that the thermal conductivity varies with the length approximately in the range of 24-34 W/m.K but exhibits insensitivity to the diameter and chirality. Besides, silicene nanotubes consisting of the grain boundary exhibit nearly 30% lower thermal conductivity compared with pristine ones. We discuss the underlying mechanism for the conductivity suppression of the system consisting of the grain boundary by calculating the phonon power spectral density. We find that by increasing the defect concentration and temperature, the thermal conductivity of the system decreases desirably. Moreover, for strained nanotubes, we observe unexpected changes in the thermal conductivity, so that the conductivity first increases significantly with tensile strain and then starts to decrease. The maximum thermal conductivity for the armchair and zigzag edge tubes appears at the strains about 3% and 5%, respectively, which is about 28% more than that of the unstrained structure.