Band-gap engineering and ballistic transport in corrugated graphene nanoribbons

摘要

We calculate the band structure and the conductance of periodic corrugatedgraphene nanoribbons within the framework of the tight-binding $p$-orbitalmodel. We consider corrugated structures based on host ribbons with armchairand zigzag edges and three different types of corrugations (armchair edges,zigzag edges as well as a rectangular corrugation). We demonstrate that forarmchair host ribbons, depending on the type of corrugation, a band gap orlow-velocity minibands appear near the charge neutrality point. For higherenergies the allowed Bloch state bands become separated by mini-stopbands. Bycontrast, for corrugated ribbons with the zigzag host, the corrugationsintroduce neither band gaps nor stopbands (except for the case of therectangular corrugations). The conductances of finite corrugated ribbons areanalyzed on the basis of the corresponding band structures. For a sufficientlylarge number of corrugations the conductance follows the number of thecorresponding propagating Bloch states and shows pronounced oscillations due tothe Fabry-Perot interference within the corrugated segments. Finally wedemonstrate that edge disorder strongly affects the conductances of corrugatedribbons. Our results indicate that observation of miniband formation incorrugated ribbons would require clean, edge-disorder free samples, especiallyfor the case of the armchair host lattice.