Tunneling conductance in graphene-based normal metal–insulator–superconductor junctions

Based on the transfer-matrix method, we have investigated the coherent quantum transport in a graphene-based normal metal–insulator–superconductor (NG/IG/SGNG/IG/SG) junctions, in the limit of a thin barrier. It is found that the conductance spectra of such system, in contrast to a π   periodic oscillatory behavior is shown for aligned Fermi surfaces of the normal and superconducting regions, exhibit a new π/2π/2 periodic oscillatory behavior as a function of barrier strength (χ) for a large Fermi surface mismatch.