  It has been shown in a recent study [Nguyen et al., Nanotechnol. \textbf{25},
165201 (2014)] that unstrained/strained graphene junctions are promising
candidates to improve the performance of graphene transistors that is usually
hindered by the gapless nature of graphene. Although the energy bandgap of
strained graphene still remains zero, the shift of Dirac points in the
\textbf{\emph{k}}-space due to strain-induced deformation of graphene lattice
can lead to the appearance of a finite conduction gap of several hundreds meV
in strained junctions with a strain of only a few percent. However, since it
depends essentially on the magnitude of Dirac point shift, this conduction gap
strongly depends on the direction of applied strain and the transport
direction. In this work, a systematic study of conduction gap properties with
respect to these quantities is presented and the results are carefully
analyzed. Our study provides useful information for further investigations to
exploit graphene strained junctions in electronic applications.
