Spin and valley dependent electronic transport in strain engineered graphene

We study the effect of the gauge potential A→S induced by a local strain on electronic transport in a strain engineered graphene junction. For the normal/strained/normal/strained/normal graphene junction, by changing the sign of A→S the K and K' valleys are interchanged, the conductance can change from finite to zero, so we obtain the valley valve effect. For the ferromagnetic/strained/ferromagnetic graphene junction in the parallel magnetization configuration by adjusting the gauge potential strength AS only the incident electrons in the spin-down channel are allowed to transmit, thus we can observe the strain-tunable spin filter effect. The magnetoresistance increases with AS and can reach up to 100%. It is expected these features may be helpful in the design of the strain-tunable spintronic devices.