Fig. 2
Schematic temperature-filling phase diagram of the 2D Hubbard model. There is long-range AF order at T = 0 for 〈n〉 = 1, a superconducting region with a Kosterlitz–Thouless18 transition line denoted by black circles, and a dashed T✶ pseudogap (PG) line marked by orange diamonds, where the q = 0 spin susceptibility peaks. The orange diamonds mark the peaks of the spin susceptibility shown in Fig. 2, and the black circles mark the temperature at which the extrapolation of the d-wave eigenvalue λd(T) reaches one. The vertical lines indicate the two fillings 〈n〉 = 0.93 and 0.85, for which the pairfield fluctuations will be studied
