Fig. 2: Illustration of the model (10) and (11).
From: Fermi-surface diagnosis for topological superconductivity with s-wave-like pairing symmetries
a shows the energy dispersion of the BdG Hamiltonian (11). b shows decomposition of the Brillouin zone, Fermi surfaces (colored solid lines), and the pairing nodes (dashed lines). The solid black lines and arrows denote the line segments specified by the gray endpoints and their orientations. The red and blue colors in the figure indicate Fermi surfaces with mirror eigenvalues  + i and  − i, respectively. The intersections of the Fermi surface and the pairing nodes correspond to the gapless points in (a). The parameters are set to be {t, λ, μ, Δ} = { − 1, 0.3, − 1, 0.3}.
