  Ever since the discovery of graphene and subsequent explosion of interest in
single atom thick materials, studying their mechanical properties has been an
active area of research. New length scales often necessitate a rethinking of
physical laws, making such studies crucial for understanding and ultimately
utilizing novel material properties. Here we report on the investigation of
nanoscale periodic ripples in suspended, single layer graphene sheets by
scanning tunneling microscopy and atomistic scale simulations. Unlike the
sinusoidal ripples found in classical fabrics, we find that graphene forms
triangular ripples, where bending is limited to a narrow region on the order of
a few unit cell dimensions at the apex of each ripple. This non-classical
bending profile results in graphene behaving like a bizarre fabric, which
regardless of how it is draped, always buckles at the same angle. Investigating
the origin of such non-classical mechanical properties, we find that unlike a
thin classical fabric, both in-plane and out-of-plane deformations occur in a
graphene sheet. These two modes of deformation compete with each other,
resulting in a strain-locked optimal buckling configuration when draped.
Electronically, we see that this in-plane deformation generates pseudo electric
fields creating a ~3 nm wide pnp heterojunction purely by strain modulation.
