Vacancy Defects Induced Layer-polarized Electron Transmission In Bilayer Graphene

We investigate the electronic transport characteristics in the zigzag bilayer graphenenanoribbons(ZBGNs) with vacancy defects, applying the nonequilibrium Green’s functionmethod combined with the tight-binding Hamiltonian and the Landauer-Butti ker formalism。The H-vacancy and T-vacancy that are formed by removing one carbon atom in differentpositions of top-layer are considered in “graphitic” AB-stacking and AA-stacking ZBGNsrespectively。Our results indicate the layer-polarized transmission can be induced by vacancy defectslocating in the outer most boundary of monolayer graphene nanoribbon for AB-stackingZBGNs。 For the AA-stacking ZBGNs, the first subband is two fold degeneracy when thewidth of sample is small, which indicates the appearance of layer-polarized transmission。 Inaddition, the band structure of the AA-stacking ZBGNs shows a particular ‘Mexican hat’shapearound the location of two valleys due to the presence of the T-vacancy。 Furthermore, it isfound that the layer-polarized transmission is robust even when a interlayer potential isconsidered。...