Fig. 5: Cartoon picture for the Fermi surfaces and the gap structure.
From: Single particle tunneling spectrum of superconducting Nd1-xSrxNiO2 thin films
a, b The Fermi surfaces and the gap amplitude at cut kz = 0. A d-wave gap is formed on the α Fermi pocket centered around Γ, and a full gap may appear on the β pocket. Actually the Fermi surface on the α pocket at this cut looks very similar to that of underdoped cuprates. The height of the colored walls in a represents gap magnitude on each Fermi surface. c, d The Fermi surfaces and the gap amplitude at the cut kz = π. A d-wave gap is formed on the α Fermi pocket centered around Z, now the Fermi surface becomes a closed square like mimicking that of overdoped cuprates, and a full gap may appear on the γ pocket around A. The height of the colored walls in c indicates the gap magnitude on each Fermi surface. The blue and red colors in b and d represent the gap signs. Note, about the full gaps on the β and γ pockets, we depict them with different colors. As mentioned in the main text, it remains unknown whether the gaps on the β and γ pockets are really fully gapped, and whether they have opposite signs.
