  In this study, we describe a new experimental approach based on
constant-current scanning tunneling spectroscopy to controllably and reversibly
pull freestanding graphene membranes up to 35 nm from their equilibrium height.
In addition, we present scanning tunneling microscopy (STM) images of
freestanding graphene membranes with atomic resolution. Atomic-scale
corrugation amplitudes 20 times larger than the STM electronic corrugation for
graphene on a substrate were observed. The freestanding graphene membrane
responds to a local attractive force created at the STM tip as a
highly-conductive yet flexible grounding plane with an elastic restoring force.
We indicate possible applications of our method in the controlled creation of
pseudo-magnetic fields by strain on single-layer graphene.
