Electronic properties of asymmetrically doped twisted graphene bilayers
Résumé
Rotated graphene bilayers form an exotic class of nanomaterials with fascinating electronic properties governed by the rotation angle θ. For large rotation angles, the electron eigenstates are restricted to one layer and the bilayer behaves like two decoupled graphene layer. At intermediate angles, Dirac cones are preserved but with a lower velocity and van Hove singularities are induced at energies where the two Dirac cones intersect. At very small angles, eigenstates become localized in peculiar moir zones. We analyse here the effect of an asymmetric doping for a series of commensurate rotated bilayers on the basis of tight binding calculations of their band dispersions, density of states, participation ratio and diffusive properties. While a small doping level preserves the θ dependence of the rotated bilayer electronic structure, larger doping induces a further reduction of the band velocity in the same way of to a further reduction of the rotation angle.
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