Vacancy-induced thermal transport in two-dimensional silicon carbide: a reverse non-equilibrium molecular dynamics study

Mia

et al. 2022

Sci Rep

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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 $$\times$$ × 10–7$${\text{Km}}^{2} /{\text{W}}$$ Km 2 / W 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.

Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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

Mia

et al. 2022

Sci Rep

Self Cite

“…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.…”

Section: Resultssupporting

confidence: 55%

“…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.…”

Section: Resultsmentioning

confidence: 99%

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

Mia

Ahammed

et al. 2020

Sci Rep

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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.

“…From a practical standpoint, when nanomaterials are synthesized experimentally or developed from their bulk counterpart, various structural defects, such as bi vacancy (BV), point vacancy (PV), ad-atoms defect, isotope defect, stone–thrower–wales defects (SW), etc., 22 , 24 − 28 are generated, and they can lessen the mechanical strength of the nanomaterial considerably because of their strong symmetry breakdown effect. Lately, the impact of diverse defects on the mechanical strength of various nanosheets such as monolayer silicon carbide, MoS 2 , germanene, and stanene has been explored.…”

Section: Introductionmentioning

confidence: 99%

Temperature- and Defect-Induced Uniaxial Tensile Mechanical Behaviors and the Fracture Mechanism of Two-Dimensional Silicon Germanide

et al. 2021

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Recently, monolayer silicon germanide (SiGe), a newly explored buckled honeycomb configuration of silicon and germanium, is predicted to be a promising nanomaterial for next-generation nanoelectromechanical systems (NEMS) due to its intriguing electronic, optical, and piezoelectric properties. In the NEMS applications, the structure is subjected to uniaxial tensile mechanical loading, and the investigation of the mechanical behaviors is of fundamental importance to ensure structural stability. Here, we systematically explored the uniaxial tensile mechanical properties of 2D-SiGe through molecular dynamics simulations. The effects of temperature ranges from 300 to 1000 K and vacancy defects, for instance, point and bi vacancy, for both armchair and zigzag orientations of 2D-SiGe were investigated. In addition, the influence of system areas and strain rates on the stress–strain performance of 2D-SiGe has also been studied. With the increase in temperature and vacancy concentration, the mechanical properties of 2D-SiGe show decreasing behavior for both orientations and the armchair chirality shows superior mechanical strength to the zigzag direction due to its bonding characteristics. A phase transformation-induced second linearly elastic region was observed at large deformation strain, leading to an anomalous stress–strain behavior in the zigzag direction. At 300 K temperature, we obtained a fracture stress of ∼94.83 GPa and an elastic modulus of ∼388.7 GPa along the armchair direction, which are about ∼3.17 and ∼2.83% higher than the zigzag-oriented fracture strength and elastic modulus. Moreover, because of the strong regularity interruption effect, the point vacancy shows the largest decrease in fracture strength, elastic modulus, and fracture strain compared to the bi vacancy defects for both armchair and zigzag orientations. Area and strain rate investigations reveal that 2D-SiGe is less susceptible to the system area and strain rate. These findings provide a deep insight into controlling the tensile mechanical behavior of 2D-SiGe for its applications in next-generation NEMS and nanodevices.