Anomalous temperature dependent thermal conductivity of two-dimensional silicon carbide

Abstract

Recently, two-dimensional silicon carbide (2D-SiC) has attracted considerable interest due to its exotic electronic and optical properties. Here, we explore the thermal properties of 2D-SiC using reverse non-equilibrium molecular dynamics simulation. At room temperature, a thermal conductivity of ∼313 W mK −1 is obtained for 2D-SiC which is one order higher than that of silicene. Above room temperature, the thermal conductivity deviates the normal 1/T law and shows an anomalous slowly decreasing behavior. To elucidate the variation of thermal conductivity, the phonon modes at different length and temperature are quantified using Fourier transform of the velocity auto-correlation of atoms. The calculated phonon density of states at high temperature shows a shrinking and softening of the peaks, which induces the anomaly in the thermal conductivity. On the other hand, quantum corrections are applied to avoid the freezing effects of phonon modes on the thermal conductivity at low temperature. In addition, the effect of potential on the thermal conductivity calculation is also studied by employing original and optimized Tersoff potentials. These findings provide a means for better understating as well as designing the efficient thermal management of 2D-SiC based electronics and optoelectronics in near future.

Understanding porosity and temperature induced variabilities in interface, mechanical characteristics and thermal conductivity of borophene membranes

“…From the extrapolation value when 1 /L → 0, we can determine intrinsic thermal conductivity values under different environmental temperatures, as shown in Fig. 10 e. In general, the higher the ambient temperature increases, the more κ is reduced, which is consistent with previous studies 54 , 55 . In addition, the results showed that κ in the zigzag direction is lower than κ in the armchair direction.…”

Exceptional in-plane and interfacial thermal transport in graphene/2D-SiC van der Waals heterostructures

“…Consequently, the estimated thermal conductivities for 100 × 10.8 nm 2 graphene ( k G ) , 2D-SiC (4) www.nature.com/scientificreports/ ( k 2D−SiC ) and the heterostructure ( k G/2d−SiC ) are 812.2113 W/m-K, 145.177 W/m-K, and 451.616 W/m-K, respectively. The obtained thermal conductivities of graphene and 2D-SiC are in line with former literature 1,23,44 . Moreover, the calculated thermal conductivity of the graphene/2D-SiC heterobilayer shows a quite high value compared to the thermal conductivities of graphene/MoS 2 45 , graphene/MoSe 2 46 , graphene/stanene 41 , silicene/ graphene 16 and individual 2D-SiC 23 of the same length.…”

“…A linear drop of temperature can be perceived from the hot area to the cold area. Earlier RNEMD simulations also reported 23,24,[42][43][44] similar phenomena for various heterobilayers as well as 2D material systems. The thermal conductivity was calculated by taking the temperature gradient, which was obtained from linear fitting.…”

“…Throughout the analysis, the total thickness of the heterobilayer was considered to be the summation of two individual monolayer thicknesses. We assumed the thickness of 2D-SiC, d 2D-SiC , and graphene, d G were 3.5 Å and 3.35 Å, respectively 23,49 . Hence, the thickness of the graphene/2D-SiC heterobilayer, d G/2D-SiC, was 6.85 Å.…”

“…The ZA phonon contributes greatly to the thermal conductivity of compound 2D materials, including 2D-GaN and 2D-ZnO. Moreover, all of these low-frequency phonon states engage in the heat conduction of 2D-SiC 23,24 . Thus, the thermal transport in the graphene/2D-SiC heterobilayer is predicted to result from the contribution of all low-frequency phonon modes.…”