Andreev reflection and momentum filtering in quantum-wire/superconductive-graphene/quantum-wire junction

Transport property of superconductive armchair graphene ribbon (AGR) connected to quantum-wire (QW) contacts is investigated via Landauer formalism combined with transfer matrix method. The scattering at the AGR/QW interface induces an obvious asymmetry in conductance as gate voltage varies. The transmission peak is located at momentum ky=2π33a with a=0.142nm. Andreev reflection (AR) enhances electronic transmission in the presence of hole reflection process. At lowest carrier density, the conductance of AGR in superconductive state becomes constant while the counterpart of semiconductive AGR in normal state decays exponentially with the length. The conductance increases with pair potential at low carrier density. The interplay between superconductivity and the scattering at the AGR/QW interface guides future application of superconductive graphene ribbon.