Tri-component-pairing chiral superconductivity on the honeycomb lattice with mixed s- and d-wave symmetries

Abstract

In this work, we investigate chiral topological superconductors on a two-dimensional honeycomb lattice with coexisting dx2−y2, dxy, and s-wave pairing symmetries. Using a Ginzburg-Landau free energy analysis, the pairing gap function is shown to exhibit a tri-component form s+dx2−y2eiϕ1+dxyeiϕ2, where ϕ1 and ϕ2 are phase differences between the d- and s-wave pairing components, which spontaneously breaks both time reversal and C6 rotational symmetries. Chern numbers of the energy bands are calculated to be nonzero, demonstrating the topologically nontrivial nature of the system. The anomalous AC Hall conductivity is computed, which is not invariant under C6 rotations, reflecting the anisotropic nature of the pairing gap function. Fractional magnetic vortices are also discussed, arising from the multicomponent nature of the pairing gap function.

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