Figure 1
Illustration: Alan Stonebraker

Figure 1: Simplified Fermi surfaces of Fe-pnictide superconductors (adapted from Fig. 1 of Ref. [13]) showing a pair of pockets at the center of the Brillouin zone with positive superconducting gap and 1/4 of a pocket pair at each of the four symmetry-equivalent zone corners with a negative gap of the same magnitude.