Majorana fermions in the s-wave kagome superconductor*

In this work, we study the kagome lattice with on-site and extended s-wave superconducting pairing and show how the inclusion of Rashba spin-orbit (RSO) interaction leads to a (time-reversal) topological superconducting state which supports helical Majorana pairs at the boundary. We calculated the Z₂ topological invariant as a function of the pairing parameters for different chemical potentials. The phase diagrams reveal topological, nodal, and trivial superconducting states depending on the system parameters. We also show how the superconducting pairing in the band basis transforms as the E_1u irreducible representation of the D₆ point group in the topological phase when RSO interaction is included, resembling a p+ip superconductor. Our work motives the exploration of Majorana fermions in the recently discovered kagome superconductors.