Non-Centrosymmetric Superconductors on Honeycomb Lattice

Non-centrosymmetric topological superconductivity is studied in correlated doped quantum spin-Hall insulators (QSHI) on honeycomb lattice without inversion symmetry where the intrinsic (Kane–Mele) and Rashba spin–orbit couplings can in general exist. The generic topologically non-trivial superconducting phase diagram of the model system is explored. Over a certain parameter range, the parity-mixing superconducting state with co-existing spin-singlet d + id and spin-triplet p + ip-wave pairing is found. On a zigzag nanoribbon, the parity-mixing superconducting state shows co-existing helical and chiral Majorana fermions at edges. The relevance of our results for experiments is discussed.