Acoustic and double elastic shock waves in single-crystal graphene

Double elastic shock waves are rarely observed in two-dimensional (2D) materials and normally unexpected for elastically isotropic 2D crystals such as graphene. With large-scale molecular dynamics simulations, we show that in single-crystal graphene shock-loaded along nonzigzag and nonarmchair directions, double elastic shock waves (quasilongitudinal and quasitransverse) can emerge. Quantitative acoustic wave equation analysis reveals that shock-induced symmetry reduction in lattice, as well as in elastic stiffness tensor, gives rise to the normally unexpected quasitransverse wave following the quasilongitudinal wave.