Fracture and strength of single-atom-thick hexagonal materials

Abstract

The fracture toughness has been theoretically and experimentally estimated for few of various two-dimensional (2D) materials. Relationship between the fracture toughness and other mechanical properties of 2D hexagonal materials is extremely needed for a quick estimation in engineering applications, as well as for a better comprehension of their fracture properties. The present work investigates through molecular dynamics simulations at room temperature the mode-I fracture of 25 single-atom-thick hexagonal materials with the buckling height-bond length ratio in the range from 0 through ∼0.6, including 6 planar sheets (graphene, boronitrene, SiC, GeC, AlN and InN) and 19 buckled sheets (silicene, InP, SiGe, SnSi, SnGe, SnO, GeO, SiO, blue-P, arsenene, GeS, SnS, antimonene, bismuthene, SiTe, SnSe, SiSe, GeTe and SnTe). Fracture mechanism is considered. With this large data set and based on dimensional analysis, an empirical formula is established to estimate the mode-I fracture toughness from the elastic modulus, intrinsic tensile strength, bond length and buckling height of a single-atom-thick hexagonal material with reasonable accuracy. This simple formula provides quick estimation of the fracture toughness and is useful for engineering applications.