  Strain fold-like deformations on armchair graphene nanoribbons (AGNRs) can be
properly engineered in experimental setups, and could lead to a new controlling
tool for gaps and transport properties. Here, we analyze the electronic
properties of folded AGNRs relating the electronic responses and the mechanical
deformation. An important and universal parameter for the gap engineering is
the ribbon percent width variation, i.e., the difference between the deformed
and undeformed ribbon widths. AGNRs bandgap can be tuned mechanically in a well
defined bounded range of energy values, eventually leading to a metallic
system. This characteristic provides a new controllable degree of freedom that
allows manipulation of electronic currents. We show that the numerical results
are analytically predicted by solving the Dirac equation for the strained
system.
