Soliton instability and fold formation in laterally compressed graphene


de Lima AL, Muessnich LAM, Manhabosco TM, Chacham H, Batista RJC, de Oliveira AB. Soliton instability and fold formation in laterally compressed graphene. NANOTECHNOLOGY. 2015;26.


We investigate-through simulations and analytical calculations-the consequences of uniaxial lateral compression applied to the upper layer of multilayer graphene. The simulations of compressed graphene show that strains larger than 2.8% induce soliton-like deformations that further develop into large, mobile folds. Such folds were indeed experimentally observed in graphene and other solid lubricants two-dimensional (2D) materials. Interestingly, in the soliton-fold regime, the shear stress decreases with the strain s, initially as s(-2/3) and rapidly going to zero. Such instability is consistent with the recently observed negative dynamic compressibility of 2D materials. We also predict that the curvatures of the soliton-folds are given by r(c) = delta root beta/2 alpha, where 1 <= delta <= 2, and beta and alpha are respectively related to the layer bending modulus and to the interlayer binding energy of the material. This finding might allow experimental estimates of the beta/alpha a ratio of 2D materials from fold morphology.