Fig. 3: Fine electronic structure of α-Bi4I4 on the (100) and (001) surfaces.
From: Topological phase transition in quasi-one-dimensional bismuth iodide Bi4I4
a, b Band structure of the (100) surface states at the \({\bar{\Gamma }}_{100}\) and \(\bar{Z}\) points measured by laser-based micro-ARPES. The green dots in (b) are determined by fitting the momentum distribution curves (MDCs) to Lorentzians and the yellow dashed lines are the fit of the extracted dispersion to the massive Dirac-fermion dispersion. c, d Curvature plots of the ARPES spectra in (a) and (b). e, f (100) surface-projected band structures calculated at the \({\bar{\Gamma }}_{100}\) and \(\bar{Z}\) points, respectively. g, h ARPES spectra of α-Bi4I4 at the \({\bar{\Gamma }}_{001}\) and \(\bar{M}\) points on the (001) surface. i, j Curvature plots of the ARPES spectra in (g) and (h). (k, l) (001) surface-projected band structures calculated at the \({\bar{\Gamma }}_{001}\) and \(\bar{M}\) point, respectively. Data were measured along the chain direction at 80 K using LH-polarized 7-eV laser.
