Strain-induced valley conductance recovery in four-terminal graphene device

Abstract

We investigated the valley dependent transport properties of a zigzag graphene ribbon attached with two strained side arms. The conductance of the zigzag ribbon for each valley is increased by the strain of the side arms. On the curves of conductance versus energy, step-like structures appear in some energy intervals, and in such intervals, the conductance does not decay when increasing the length of the intersection region. By applying a strain exceeding a critical amount, the conductance of valley K (K′) for the negative (positive) energies can be recovered to that of a graphene ribbon without side arms attached. The critical strain is compressive and is evaluated as about −10%. We explained all the features by means of the energy dispersion of the injection ribbon and that of the strained region.