Temperature and interlayer coupling induced thermal transport across graphene/2D-SiC van der Waals heterostructure.

Graphene based two-dimensional (2D) van der Waals (vdW) materials have attracted enormous attention because of their extraordinary physical properties. In this study, we explore the temperature and interlayer coupling induced thermal transport across the graphene/2D-SiC vdW interface using non-equilibrium molecular dynamics and transient pump probe methods. We find that the in-plane thermal conductivity κ deviates slightly from the 1/T law at high temperatures. A tunable κ is found with the variation of the interlayer coupling strength χ. The interlayer thermal resistance R across graphene/2D-SiC interface reaches 2.71 [Formula: see text] 10-7 [Formula: see text] at room temperature and χ = 1, and it reduces steadily with the elevation of system temperature and χ, demonstrating around 41% and 56% reduction with increasing temperature to 700 K and a χ of 25, respectively. We also elucidate the heat transport mechanism by estimating the in-plane and out-of-plane phonon modes. Higher phonon propagation possibility and Umklapp scattering across the interface at high temperatures and increased χ lead to the significant reduction of R. This work unveils the mechanism of heat transfer and interface thermal conductance engineering across the graphene/2D-SiC vdW heterostructure.

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

Graphene based van der Waals heterostructures (vdWHs) have gained substantial interest recently due to their unique electrical and optical characteristics as well as unprecedented opportunities to explore new physics and revolutionary design of nanodevices. However, the heat conduction performance of these vdWHs holds a crucial role in deciding their functional efficiency. In-plane and out-of-plane thermal conduction phenomena in graphene/2D-SiC vdWHs were studied using reverse non-equilibrium molecular dynamics simulations and the transient pump-probe technique, respectively. At room temperature, we determined an in-plane thermal conductivity of ~ 1452 W/m-K for an infinite length graphene/2D-SiC vdWH, which is superior to any graphene based vdWHs reported yet. The out-of-plane thermal resistance of graphene → 2D-SiC and 2D-SiC → graphene was estimated to be 2.71 × 10-7 km2/W and 2.65 × 10-7 km2/W, respectively, implying the absence of the thermal rectification effect in the heterobilayer. The phonon-mediated both in-plane and out-of-plane heat transfer is clarified for this prospective heterobilayer. This study furthermore explored the impact of various interatomic potentials on the thermal conductivity of the heterobilayer. These findings are useful in explaining the heat conduction at the interfaces in graphene/2D-SiC vdWH and may provide a guideline for efficient design and regulation of their thermal characteristics.

Lateral and flexural thermal transport in stanene/2D-SiC van der Waals heterostructure.

Thermal management is one of the key challenges in nanoelectronic and optoelectronic devices. The development of a van der Waals heterostructure (vdWH) using the vertical positioning of different two-dimensional (2D) materials has recently appeared as a promising way of attaining desirable electrical, optical, and thermal properties. Here, we explore the lateral and flexural thermal conductivity of stanene/2D-SiC vdWH utilizing the reverse non-equilibrium molecular dynamics simulation and transient pump-probe technique. The effects of length, area, coupling strength and temperature on the thermal transport are studied systematically. The projected lateral thermal conductivity of a stanene/2D-SiC hetero-bilayer is found to be 66.67 [Formula: see text], which is greater than stanene, silicene, germanene, MoSe2 and even higher than some hetero-bilayers, including MoS2/MoSe2 and stanene/silicene. The lateral thermal conductivity increases as the length increases, while it tends to decrease with increasing temperature. The computed flexural interfacial thermal resistance between stanene and 2D-SiC is 3.0622 [Formula: see text] [Formula: see text] K.m2 W-1, which is close to other 2D hetero-bilayers. The interfacial resistance between stanene and 2D-SiC is reduced by 70.49% and 50.118% as the temperature increases from 100 K to 600 K and the coupling factor increases from [Formula: see text] to [Formula: see text], respectively. In addition, various phonon modes are evaluated to disclose the fundamental mechanisms of thermal transport in the lateral and flexural direction of the hetero-bilayer. These results are important in order to understand the heat transport phenomena of stanene/2D-SiC vdWH, which could be useful for enhancing their promising applications.