Majorana vortex modes in spin-singlet chiral superconductors with noncollinear spin ordering: Local density of states study

In the present study topologically nontrivial edge and vortex bound states are described in the coexistence phase of chiral spin-singlet superconductivity and noncollinear spin ordering on a triangular lattice. Since chiral superconductivity is nodeless in a wide range of parameters, the obtained bound states are separated from trivial bulk states. It is proved that Majorana modes localized at vortex cores are caused by noncollinear long-range magnetic ordering. Even though nearby excitation energies of subgap states including the edge-localized and vortex-localized states are very close to each other, the energy difference between different vortex bound states is an order of magnitude higher. It opens the way to experimentally detect the zero energy Majorana modes localized at vortex cores in the considered structures by using methods measuring local density of states such as tunneling experiments. For a few pairs of vortices, vortex bound states with near zero energy can appear. Nevertheless, they are localized on different vortices in comparison with the localization of Majorana vortex modes. In this case zero modes are still separated in energy and space from other states in local density of states results. The difference between density of states near the vortex and near the antivortex hosting Majorana modes is also demonstrated.Comment: 10 pages, 10 figure