Fig. 1: Edge and corner modes of single-layer FeSe.
From: Identifying s-wave pairing symmetry in single-layer FeSe from topologically trivial edge states
a Schematic illustration of the Fermi surface of single-layer FeSe consisting of two electron pockets centered at the M point of the Brillouin zone (black dashed lines). Different colors denote the opposite sign of order parameters. The left, middle, and right panels depict nodeless d-, sign-changing s±-, and sign-preserving s-wave pairings with band hybridization taken into account, respectively. b Definition of edges and the corner. The blue and red cones indicate the band structures at various edges in the case of s- and s±-wave pairing, respectively. The lower right panel indicates zero-energy modes for the s±-wave case. c Supposed tunneling spectra at the (11) and (01) edges and the corner for the s- (blue) and s±-wave (red) cases. The gray lines are spectra away from the edge/corner. The main contributions of the Dirac mode and the Majorana mode to the tunneling spectrum are highlighted in red shading. The horizontal axis is normalized by the superconducting energy gap \(\Delta\).
