Elastic and nonlinear stiffness of graphene: A simple approach

The recent experiment C. G. Lee et al. [Science 321, 385 (2008)] on the Young's modulus and third-order elastic stiffness of graphene are well explained in a very simple approach, where the graphene is described by a simplified system and the force constant for the nonlinear interaction is estimated from the Tersoff-Brenner potential.