Extended Data Fig. 3: Theoretical study of the electronic structure of the (001) surface of β-Bi4I4.
From: A weak topological insulator state in quasi-one-dimensional bismuth iodide
a–d, Calculated bulk band dispersions for the \(\bar{{\rm{M}}}\) and \(\bar{\Gamma }\) points of the (001) surface, depending on the topological phase. Colours denote different kz values. e–h, Calculation of the band structures, including surface states (SS), for the \(\bar{{\rm{M}}}\) and \(\bar{\Gamma }\) points of the (001) surface depending on the topological phase.
