  In order to harvest the many promising properties of graphene in (electronic)
applications, a technique is required to cut, shape or sculpt the material on a
nanoscale without damage to its atomic structure, as this drastically
influences the electronic properties of the nanostructure. Here, we reveal a
temperature-dependent self-repair mechanism allowing damage-free atomic-scale
sculpting of graphene using a focused electron beam. We demonstrate that by
sculpting at temperatures above 600 {\deg}C, an intrinsic self-repair mechanism
keeps the graphene single-crystalline during cutting, even thought the electron
beam induces considerable damage. Self-repair is mediated by mobile carbon
ad-atoms constantly repairing the defects caused by the electron beam. Our
technique allows reproducible fabrication and simultaneous imaging of
single-crystalline free-standing nanoribbons, nanotubes, nanopores, and single
carbon chains.
