Fig. 3: Electronic structures of 2D Cr₈Se₁₂ on graphite.

a The geometric relation between the BZs of 2D Cr₈Se₁₂ (orange), 2D Cr₂Se₃ (blue), and the graphite substrate (black). b Second-derivative ARPES dispersion of the as-grown chromium selenide on graphite, which is measured at T = 40 K and displayed along the Γ-M₁-K₂ and Γ-K₁-M₂ directions as defined in Fig. 3a. The DFT band structure of 2D Cr₂Se₃ (blue, Supplementary Fig. 17) and unfolded band structure of 2D Cr₈Se₁₂ (orange, Supplementary Fig. 15) are superimposed for comparison with the ARPES data. The partial flat band near the M₁ point is marked by a white dashed rectangle. c Constant energy contour at Fermi level. Scale bar: 0.5 nm⁻¹. The Dirac cones of the graphite at Fermi level are marked by black arrows in Fig. 3c. d The schematic crystal structures of the topmost two atomic adlayers for cross comparison with Fig. 3f–k. Three types of triangles are marked by different colors. e Energetically aligned dI/dV spectrum acquired on 2D Cr₈Se₁₂. (V_s = 0.30 V, I = 100 pA, f = 963 Hz, V_r.m.s. = 10 mV, T = 4.3 K). f-h Constant-height dI/dV maps of 2D Cr₈Se₁₂ acquired at the same region and at energies corresponding to the (f) CBM (V_s = 20 mV), (g) VBM (V_s = −0.8 V), and (h) VHS (V_s = −1.1 V), respectively. i–k DFT simulated charge density distributions of 2D Cr₈Se₁₂ acquired at energies corresponding to the (f) CBM, (g) VBM, and (h) VHS, respectively. Three types of triangles are marked by different colors as in panel (d).