Equi-biaxial compressive strain in graphene: Grüneisen parameter and buckling ridges

摘要： Here we report equi-biaxial compressive strain in monolayer graphene on SiO2 and Si3N4 substrates induced by thermal cycling in vacuum. The equi-biaxial strain is attributed to the mismatch in coefficient of thermal expansion between graphene and the substrate and sliding of graphene on the substrate. Importantly, the induced buckling ridges in graphene exhibit a pattern representing the symmetry of graphene crystal structure, which agreed well with our molecular dynamics (MD) simulations. Furthermore, these thermally-induced buckling ridges were found reminiscent of those in graphene synthesized by the CVD and SiC sublimation methods, suggesting the same origin of formation of the buckling ridges.