Fig. 2: Distinguish the bulk and surface VBs from momentum-resolved O 2p spectra.
a Upper panel: The bulk BZ and the projected surface BZ. Blue shade indicates the bulk bct structure of primitive cell. Orange shade indicates the bulk st structure of unit cell. The top orange shade is the projected surface 2D structure. Lower panel: surface (1 × 4) reconstructed BZ. b The raw ARPES cut excited by hυ = 21.2 eV along the high-symmetry axes and the corresponding EDC at \(\bar{\Gamma }\) point. c The second derivative cut from b, overlaid with the calculated bulk VBs at the corresponding kz (\({{{{{\rm{\delta }}}}}}^{\prime} \sim 0.5\)) (yellow dashed lines, see details in Supplementary Fig. 1). The calculated VBs have been shifted to maximize the overlap with the experimental results. White arrows: surface levels of S1, S2 bands. d The calculated pDOSs of OBLUK, OTERRACE, OSIDE, OTOP-ADM and OTOP-AOM, based on the ADM (solid lines) and AOM (dotted lines) models. e The extracted electronic states of S1, S2 and VBM bands of the ADM model at \(\bar{\Gamma }\) point, exhibiting localized spatial distributions at the OTERRACE, OSIDE, and OTOP-ADM atoms, respectively. f Calculated VB dispersion according to the weightings of surface OTERRACE and OSIDE sites, respectively. The OTERRACE bands involve the main feature of S1 and the OSIDE involve the main feature of S2, respectively.
