Klein paradox and resonant tunneling in a graphene superlattice

This paper studies the transport properties of charge carriers through graphene superlattices consisting of monolayer or bilayer graphene on the basis of the transfer-matrix method. Emphasis is placed on the relationship between the Klein paradox and resonant tunneling in double-barrier junctions. It is shown that normal incidence transmission probabilities for two kinds of graphene structure exhibit different features. Independent of structure parameters, they are always perfectly transmitted in a monolayer graphene structure. In contrast, the transmission resonances occur in a bilayer graphene structure. However, the angularly averaged conductivities for both depend on the thickness and height of the barriers as well as the width and number of the well. That is to say, the angularly averaged conductivities in monolayer and bilayer graphene superlattices can be controlled by changing the structure parameters even if Klein tunneling exists.