Tuning the thermal conductivity of silicene with tensile strain and isotopic doping: A molecular dynamics study

Abstract

Silicene is a monolayer of silicon atoms arranged in honeycomb lattice similar to graphene. We study the thermal transport in silicene by using non-equilibrium molecular dynamics simulations. We focus on the effects of tensile strain and isotopic doping on the thermal conductivity, in order to tune the thermal conductivity of silicene. We find that the thermal conductivity of silicene, which is shown to be only about 20% of that of bulk silicon, increases at small tensile strains but decreases at large strains. We also find that isotopic doping of silicene results in a U-shaped change of the thermal conductivity for the isotope concentration varying from 0% to 100%. We further show that ordered doping (isotope superlattice) leads to a much larger reduction in thermal conductivity than random doping. Our findings are important for the thermal management in silicene-based electronic devices and for thermoelectric applications of silicene.

A molecular dynamics simulation study on thermal conductivity of functionalized bilayer graphene sheet

“…Strain engineering is widely used in the manipulation of the thermal properties of nanomaterials [28,29]. In the following, we will investigate how the thermal conductivity responds to the external tensile strain by performing simulations on GMix models with 1% coverage for illustration purpose.…”

Resolving anomalous strain effects on two-dimensional phonon flows: The cases of graphene, boron nitride, and planar superlattices

“…Nevertheless, as the strain increases, the nature of the flow changes from ballistic-dominant towards diffusive-dominant. Although it is difficult to determine the precise physical mechanism underpinning the decrease of Kn, it is feasible that it arises from the softening of bonds when tensile strain is applied (discussed later), which can introduce inter-phonon scattering and reduce mean free paths 12,24 .…”

Phonon thermal conduction in novel 2D materials

“…Unlike graphene in which all carbon atoms form honey-cone structures within a flat plane, silicon atoms in silicone show a buckled structure, resulting in unique thermal transports fundamentally differing from that in other 2D materials, namely (a) longitudinal and transverse acoustic phonons dominate the thermal transports and the acoustic out-of-plane phonon modes only have less than 10% contributions to the total thermal conductivity [114][115][116][117]; (b) thermal conductivity increases dramatically with tensile strain due to enhancement in acoustic phonon lifetime [118][119][120]. Unfortunately, no experiment on thermal conductivity in silicene has been reported.…”