Multiple Dirac points and perfect transmission in graphene with a dimerlike potential

Abstract

In this work, we investigate electronic band structures and transport properties in dimerlike graphene superlattices (DGSLs), where the modulated potentials of square barrier A and well B on graphene are arranged as S(m) = (AB)m(BA)m. Here m is the repeated number of units. It is found that the mirror symmetry of the potential distribution on graphene can induce extra Dirac points (DPs), which originates from the dimerlike positional correlations in the system. The induced DPs, which are exactly located at the energy corresponding to zero averaged wave number, do not exist in the periodic graphene superlattices of (AB)m. The number and the position of DPs in the zero averaged wave number gap of DGSL can be manipulated. Correspondingly, multiple perfect transmissions are observed at the resonant modes. Moreover, the conductance for DGSL presents extra resonant peaks accompanying with the emergence of the induced DPs. The investigations may have potential applications in graphene-based electronic devices.