Journal of Physics D: Applied Physics 49, 045306 (2016)

ISSN: 0022-3727, SCI

Transport gap in vertical devices made of incommensurately misoriented graphene layers

V Hung Nguyen, and P Dollfus

By means of atomistic tight-binding calculations, we investigate the transport properties of vertical devices made of two incommensurately misoriented graphene layers. For a given transport direction (Ox-axis), we define two classes of rotated graphene lattice distinguished by difference in lattice symmetry and, hence, in Brillouin zone. In particular, these two classes correspond to two different cases where the position of their Dirac cones in the ky-axis is determined differently, i.e. K'y = Ky = 0 or K'y = −Ky = 2π/3Ly (Ly is the periodic length along the Oy axis). As a consequence, in devices made of two layers of different lattice classes, the misalignment of Dirac cones between the left and right graphene sections opens a finite energy-gap of conductance that can reach a few hundreds of meV. We also show that strain engineering can be used to further enlarge the transport gap and to diminish the sensitivity of the gap on the twist angle and on the commensurateness of the layer stack.

DOI: 10.1088/0022-3727/49/4/045306

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