Figure 1. d-wave superconducting phase obtained by the plaquette CDMFT solution of the two-dimensional Hubbard model.

We explore the T − U − δ space by taking cuts at n = 1 as a function of U and T [panel (a)] and at constant U as a function of δ and T [panels (b–g)]. Superconductivity is delimited by (line with blue filled circles), the temperature below which the superconducting order parameter Φ is nonzero. Color corresponds to the magnitude of |Φ| (see supplementary Fig. S1 for Φ(U) and Φ(δ) curves at different T). The loci of Φ_max(δ) are shown by blue triangles. On the right vertical axis we convert temperature to Kelvin by using t = 0.35eV. The coexistence region across the first-order Mott metal-insulator transition appears in panel (a) as red shaded area. It is obtained from the hysteretic evolution of the double occupancy with U¹⁴.