Fig. 4: CD-ARPES band dispersions.

a–c CD-ARPES plots taken at 13 K. The measurement geometries are the same as those in Figs. 2 and 3. d Schematic drawing of the OAM polarizations corresponding to surface FCs, assuming that they are parallel to the helicities of the incident-photon polarizations: parallel (anti-parallel) to the photon-incidence vector for right- (left-) handed polarization. Fat lines indicate the cut orientations shown in (a–c). Circled digits indicate number of surface FCs in SBZ. e Surface FCs folded by (2 × 2) SBZ boundary. Arrows guide the possible singularity points (see main text for details). f Schematic drawings of TSS with folding and distortion from the anisotropic surface superstructure.