Paper on localized folding in supported graphene

http://jap.aip.org/resource/1/japiau/v113/i19/p193501_s1 

Localized folds are commonly observed in supported graphene, e.g. in CVD-grown samples. Such folds affect the electronic and chemical properties of graphene, and therefore draw an increasing interest in understanding their mechanism. In this paper, we systematically study the emergence and morphology of folds in supported and laterally strained graphene with simulations relying on an atomistic-based continuum model, and with a nonlinear theoretical model. We find that localized folding in supported graphene is preceded by uniformly distributed wrinkles with very small amplitude, and due to the nonlinearity in the van der Waals interactions between graphene and the substrate. We identify friction as a selection mechanism for the separation between folds, as the formation of far apart folds is penalized by the work of friction.