  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.
