  Advancement of nanotechnology has greatly accelerated the miniaturization of
mechanical or electronic devices. This work proposes a new nanoscale spring - a
graphene nanoribbon-based helicoid (GH) structure by using large-scale
molecular dynamics simulation. It is found that the GH structure not only
possesses an extraordinary high tensile deformation capability, but also
exhibits unique features not accessible from traditional springs. Specifically,
its yield strain increases when its inner radius is enlarged, which can exceed
1000%, and it has three elastic deformation stages including the initial
delamination, stable delamination and elastic deformation. Moreover, the
failure of the GH is found to be governed by the failure of graphene nanoribbon
and the inner edge atoms absorb most of the tensile strain energy. Such fact
leads to a constant elastic limit force (corresponding to the yield point) for
all GHs. This study has provided a comprehensive understanding of the tensile
behaviors of GH, which opens the avenue to design novel nanoscale springs based
on 2D nanomaterials.
