Electric-field-induced penetration of edge states at the interface between monolayer and bilayer graphene

The edge states in the hybrid system of single-layer and double-layer graphene are studied in the tight-binding model theoretically. The edge states in one side of the interface between single-layer and double-layer graphene are shown to penetrate into the single-layer region when the perpendicular electric field is applied, while they are localized in the double-layer region without electric field. The edge states in another side of the interface are localized in the double-layer region independent of the electric field. This field-induced penetration of the edge states can be applied to switching devices. We also find a new type of the edge states at the boundary between single-layer and the double-layer graphene.