Fig. 4: Theoretical calculation results of Si/Ag(001).

a DFT calculated band structure of Si/Ag(001) along the \(\bar{{{{{{\rm{M}}}}}}}-\bar{{{{{{\rm{X}}}}}}}-\bar{{{{{{\rm{M}}}}}}}\) direction of Ag(001). b–e DFT calculated band structures for comparison with ARPES spectra along Cuts 1-4 in Fig. 3. The calculated band structures are projected onto the Si and topmost Ag layer. Blue dashed lines are guides to the eye for comparison with ARPES measurement results. The marker size and color represent the spectral weight that comes from the projection of the supercell wavefunction to the BZ of the primitive cell. f Schematic drawing of the TB model. There are four Si atoms in each unit cell, as indicated by the numbers 1-4. g, h Calculated band structure based on the TB model. Parameters: \({t}_{1\pi }=1.2\) eV, \({t}_{2\sigma }={t}_{2\pi }=1.15\) eV, \({t}_{3\pi }=0.25\) eV, and \({U}_{1}=2.5\) eV, \({U}_{2}=0.45\) eV. i Edge spectrum of the nontrivial edge which is obtained by cutting the system through the centers of the blue bonds (the Wannier center) in the y direction. j Edge spectrum of the trivial edge by cutting the bonds in the x direction.