We have investigated the transport properties of a Kane-Mele normal-superconductor (NS) nano-junction using the familiar Blonder-Tinkham-Klapwijk (BTK) theory. The effects of the Rashba and the intrinsic spin-orbit coupling are mimicked by the inclusion of different transition metal adatoms adsorbed in a graphene nanoribbon. Specifically, we have focussed on the Andreev reflection phenomena for a range of Rashba and intrinsic coupling strengths. We have computed the spin resolved tunneling conductance where we found that the conductance characteristics are very sensitive to the strengths of the spin-orbit couplings. Further an interesting interplay between the Rashba and the intrinsic spin-orbit couplings is observed and its effects on the tunneling conductance are explored in detail. The possibility of tuning the spin-orbit couplings via different metal adatoms provides an experimental handle for achieving tunable conductance properties of this Kane-Mele nano-junction.
Published in: "EPL".