The mechanical properties of three types of carbon allotropes

摘要

The mechanical properties of supergraphene, cyclicgraphene and graphyne are studied using molecular dynamics simulations based on the AIREBO potential. In particular, we present the chirality-dependence of their mechanical properties, including Young's moduli, shear moduli, Poisson's ratios, ultimate strength and ultimate strains. The relationship of their Young moduli, shear moduli and Poisson ratios is in the order of Y_(su) (super) < Y_(cy) (cyclic) < Y_(gy) (graphyne) < Y_(ge) (graphene), G _(su) < G_(cy) < G_(gy) < G_(ge) and v_(su) > v_(cy) > v_(gy) > v_(ge) in corresponding zigzag and armchair sheets, respectively. Their intersheet adhesion energy is obtained as γ_(su) = 30, γ_(cy) = 99 and γ_(gy) = 149 mJ m~(-2), which are much lower than that of γ_(ge) = 291 mJ m~(-2) (the value is in good agreement with the latest experimental result γ_(ge) = 310 ± 30 mJ m~(-2)). The obtained adhesion energy is accurately characterized by continuum modeling of the van der Waals interactions. Our study is very useful for the future applications of graphene-like materials in nanoelectromechanical systems.