Extended Data Fig. 7: Orbital characters of the TSSs in β-Bi4I4.
From: A weak topological insulator state in quasi-one-dimensional bismuth iodide
a, Calculated constant energy contour for the (100) surface of β-Bi4I4. The energy is set at 0.05 eV to allow comparison with the Fermi surface obtained by ARPES experiment. b, Orbital separated spectra, calculated with the p-orbital model, of the surface electronic structure around the \(\bar{\Gamma }\) point of the (100) surface (red arrow in a). Each subpanel shows the contribution of the px, py and pz orbitals for Bi, I and all elements. The directions of the px,y,z orbitals are defined relative to the (100) surface, as illustrated in a. c, The same results as b, but for the momentum cut across the \(\bar{{\rm{Z}}}\) point (orange arrow in a).
