Figure 4: Molecular dynamics (MD) simulations of brittle fracture in a monolayer single-crystal graphene with a pre-crack.
(a) Atomic structure of a graphene slab containing a central crack. The zoom-in image shows the near-tip structure as well as the crack face with the zigzag edge. (b) An intermediate state of fast crack propagation. (c) The final state of cleavage fracture, resulting in atomically smooth edges. (d) Corresponding stress-strain curve of the pre-cracked graphene during fracture. (e) Effect of the pre-crack length 2a0 on the product of 
. (f) Effect of blunting of the crack tip with different notch radii of r. In (e,f), MD results (circles) are compared with the prediction (dashed line) from the Griffith theory of brittle fracture.
