Fig. 4: Simulated spectral function in amorphous lattice.
From: Establishing coherent momentum-space electronic states in locally ordered materials
a Average site occupations for wavefunctions with energy within the bulk gap (yellow) and below the bulk gap (blue). b Single surface state wavefunction (E − EF = 0 yellow) is delocalized along the surface plane, spreading across multiple unit cells. Single bulk state wavefunctions (E − EF < − 0.5 eV red, green blue) are localized within the bulk. c Measure of mean free-path (or spatial coherence) of surface state electrons as a function of kz as determined experimentally from 2π/σMDC for c-Bi2Se3 and a-Bi2Se3 from Fig. 3d, e. d Spectral function of a linear dispersing state scattered on a disordered array of atoms with increasing scattering strengths v0. (1) no scattering (continuous medium), (2) weak atomic scattering strength, (3) full effect of the atomic lattice. When the scattering strength increases, copies of the central Dirac cone appear at the peaks of c2, i.e. around k = ± 0.4 Å−1. For strong enough scattering potential, the dispersion is pushed into the valence band and broad vertical features form that cross the bulk band gap. e Experimental ARPES spectrum and the same spectrum normalized along the energy-axis for comparison with simulation.
