Fig. 4: Projected pairing kernels and gap functions.
From: Superconductivity in kagome metals due to soft loop-current fluctuations
The singlet-channel pairing interaction for two LC patterns a–f and examples of SC gap functions they result in (g)–(i). Under (a)–(f), one momentum of the interaction k* is fixed to the white point, which is on a Fermi surface, while the other momentum k is varied across the remaining Fermi surface area, with red color indicating the degree of repulsion. As mentioned in the discussion, the singlet interactions is always repulsive for interactions mediated by LCs. a–c show the interaction for the V-V \(m{M}_{2}^{+}\) pattern of Fig. 3a. d–f correspond to the V-Sb \(m{M}_{2}^{+}\) patterns of Fig. 3c. In (g) we show the basis gap function for \({d}_{{x}^{2}-{y}^{2}}\) pairing, in (h) for dxy, and in (i) for s±. In hexagonal systems, \({d}_{{x}^{2}-{y}^{2}}\) and dxy belong to the same two-dimensional irrep, namely E2g. All plots in this figure were generated for mass r = 0.3, and used the phenomenological propagator from Eq. (3). Using the RPA propagator yields indistinguishable results for the pairing states.
