  We theoretically investigate the spin-charge transport in two-terminal device
of graphene nanoribbons in the presence of an uniform uniaxial strain,
spin-orbit coupling, exchange field and smooth staggered potential. We show
that the direction of applied strain can efficiently tune strain-strength
induced oscillation of band-gap of armchair graphene nanoribbon (AGNR). It is
also found that electronic conductance in both AGNR and zigzag graphene
nanoribbons (ZGNRs) oscillates with Rashba spin-orbit coupling akin to the
Datta-Das field effect transistor. Two distinct strain response regimes of
electronic conductance as function of spin-orbit couplings (SOC) magnitude are
found. In the regime of small strain, conductance of ZGNR presents stronger
strain dependence along the longitudinal direction of strain. Whereas for high
values of strain shows larger effect for the transversal direction.
Furthermore, the local density of states (LDOS) shows that depending on the
smoothness of the staggered potential, the edge state of AGNR can either emerge
or be suppressed. These emerging states can be determined experimentally by
performing spatially scanning tunneling microscope or by scanning tunneling
spectroscopy. Our findings open up new paradigms of manipulation and control of
strained graphene based nanostructure for application on novel topological
quantum devices.
