Figure 3: Probing the electronic band structure by ARPES measurements.
From: Sn-doped Bi1.1Sb0.9Te2S bulk crystal topological insulator with excellent properties
(a) The ARPES-determined band dispersion for ky along M–Γ–M measured at 30 eV photon energy, at 15 K. The bands were electron doped through deposition of potassium (K), to allow for the determination of the energy of the conduction band minimum. (b) Excerpts from the excitation energy dependence (hv=82, 74 and 66 eV) study of the photoemission from the electron-doped bands reflect the perpendicular momentum kz positions of the BVB and BCB extrema. The SSs are unaffected by the change of kz. (c) A schematic for the electronic structure of Sn-BSTS in the vicinity of the Fermi energy derived from the ARPES data. Grey dashed lines mark the bulk band gap region, two crossed red lines correspond to the SSs and the turquoise line shows the position of the DP. The constant-energy ARPES maps, referenced relative to the Fermi level EF for the pristine sample (g–i) or the DP EDP for the K-deposition-generated electron-doped sample (d,e), showing a few critical points in the low-energy band structure of Sn-BSTS. (f) A schematic for Brillouin zone with high symmetry points.
