Thermal Transport of Graphene Sheets with Fractal Defects

Abstract

Graphene combined with fractal structures would probably be a promising candidate design of an antenna for a wireless communication system. However, the thermal transport properties of fractal graphene, which would influence the properties of wireless communication systems, are unclear. In this paper, the thermal transport properties of graphene with a Sierpinski fractal structure were investigated via the reverse non-equilibrium molecular dynamics simulation method. Simulation results indicated that the thermal conductivity of graphene with fractal defects decreased from 157.62 to 19.60 (W m−1 K−1) as the fractal level increased. Furthermore, visual display and statistical results of fractal graphene atomic heat flux revealed that with fractal levels increasing, the real heat flux paths twisted, and the angle distributions of atomic heat flux vectors enlarged from about (−30°, 30°) to about (−45°, 45°). In fact, the fractal structures decreased the real heat flow areas and extended the real heat flux paths, and enhanced the phonon scattering in the defect edges of the fractal graphene. Analyses of fractal graphene thermal transport characters in our work indicated that the heat transfer properties of fractal graphene dropped greatly as fractal levels increased, which would provide effective guidance to the design of antennae based on fractal graphene.

Atomistic simulations of phonon behaviors in isotopically doped graphene with Sierpinski carpet fractal structure

“…The minimum thermal conductivity of SC fractal structures is 585.20 W m −1 K −1 with a fractal number of 6, and the corresponding reduction ratio is 52.37%. A similar decline trend in low fractal number region is observed in other work [25]. We attribute this phenomenon to the phonon mode localization.…”

“…It can be observed that the enhanced phonon scattering at the Si/Ge interfaces makes the larger reduction of thermal conductivity in SC fractal structures in comparison with the regular carpet structures. Moreover, Kang et al evaluate the thermal conductivity of graphene with SC fractal defects by employing the MD method [25]. They observe that when the fractal number increases from 0 to 3, the thermal conductivity drops from 164.40 to 19.60 W m −1 K −1 .…”

Lattice thermal transport in two-dimensional alloys and fractal heterostructures

“…where e, v i , and S i j are the energy, velocity vector, and local stress tensor at each atom 53,54 . Figure 3b shows the computed per-atom flux through the fractal-patterned MoSe 2 /WSe 2 heterostructure.…”

Molecular Dynamics Investigation on Thermal Conductivity and Photon Behaviors of Graphene With Sierpinski Carpet Fractal Defects

“…Considering the structure of self-similarity in nature, nanofabrication technologies are adopted to construct selfsimilar structures (Zhang et al, 2014;Deng et al, 2017;Zhang et al, 2020). As one of the self-similar set, the Sierpinski carpet fractal (SCF) structure is introduced to construct the defective graphene (Kang et al, 2018;Han et al, 2019a;Han et al, 2020). The SCF defects in graphene can significantly increase the boundary scattering of phonon and thus significantly reduce the TC (Zhang et al, 2014;Wei et al, 2015;Shao et al, 2018).…”

“…The SCF defects in graphene can significantly increase the boundary scattering of phonon and thus significantly reduce the TC (Zhang et al, 2014;Wei et al, 2015;Shao et al, 2018). When the fractal level increases from 0 to 3, the TC of the SCF graphene monolayer decreases from 164.4 to 19.6 W/mK (Kang et al, 2018).…”