Fig. 2: Crossings between the bilayer-split shadow and the main bands.

E(k_z) ARPES intensity plots measured at 100 K for k_x = a 0.68, b 0.63, c 0.59, and d 0.56 Å⁻¹. The red and blue dots at the top of the panels indicate the k_z positions of the ΓX and Γ₂X₂ high symmetry lines. The white dashed arrows in panels a and b represent the q_CDW and the band crossing regions are highlighted by green dashed ovals. E = 0 represents the E_F. These panels share same y axis and colorbar, the latter is shown on the right of panel d. e A zoomed view of the near E_F region of panel a around k_z = 0.21 Å⁻¹, the dashed red (black) line that represents the main (shadow) band is obtained by curve fitting (see Methods). The double-sided red arrows show the bilayer splitting. f Curvature plot of a part of panel c shown in an expanded scale: the L, B, R and T crossings are highlighted by blue, black, yellow and red rectangles, respectively. The T and B crossings occur on the Γ₂X₂ line. The dashed red [black] lines representing the bilayer split main (mu,md) [shadow (su,sd)] bands are obtained by curve fitting as in e. e, f share the same colorbar. g Cut A at k_z = 0.216 of an E-k_z-k_x ARPES intensity plot shows the dispersion of the R crossing and the mu and sd bands within the yellow rectangle. A shadow band is observed in the cut B. The ARPES cuts measured along the red lines a-d on the k_x axis are shown in panels a–d. h–k The effective band structure (EBS) along k_z obtained by band unfolding at similar k_x values as in a–d, respectively. The intensity scale represents the spectral weights calculated from band unfolding and the size of the dots is related to the instrumental resolution. h–k share same y axis and colorbar, the latter is shown on the right of k. The double-sided red arrows indicate the bilayer splitting and the blue arrows in panel h represent the q_CDW. The band crossing regions are highlighted by green dashed ovals.