Valley polarized electronic transmission through a line defect superlattice of graphene

The band structure of a one-dimensional superlattice formed by patterning graphene lattice with a periodic line defect array is calculated. The lowest conduction subband of such a superlattice connects two inequivalent Dirac points with flat dispersion, which is reminiscent of the flat-bottomed subband of a zigzag-edged graphene nanoribbon (ZEGNR). According to such a subband characteristic, a finite length line defect superlattice in graphene, instead of a ZEGNR, can be utilized to realize valley filtering function. The calculated electronic transmission spectrum of such a structure shows the nearly perfect valley polarization for low energy incident electrons.