Non-centrosymmetric superconductors on honeycomb lattice

TL;DR

This paper investigates topological superconductivity in doped honeycomb lattice systems lacking inversion symmetry, revealing a parity-mixing state with co-existing Majorana edge modes, relevant for experimental realization.

Contribution

It introduces a comprehensive phase diagram for non-centrosymmetric superconductivity on honeycomb lattices, highlighting a novel parity-mixing state with potential Majorana fermions.

Findings

Parity-mixing superconducting state with $d+id$ and $p+ip$ pairing

Co-existence of helical and chiral Majorana fermions at edges

Topologically non-trivial phase diagram for the model system

Abstract

We study non-centrosymmetric topological superconductivity 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. We explore the generic topologically non-trivial superconducting phase diagram of the model system. Over a certain parameter space, 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. Relevance of our results for experiments is discussed.