Extended Data Fig. 2: Theoretical study of the electronic structure of α-Bi4I4.
From: A weak topological insulator state in quasi-one-dimensional bismuth iodide
a, The first Brillouin zone of α-Bi4I4. b, Bulk band structures calculated by GGA without SOC (left), with SOC (middle) and by GGA plus mBJ with SOC (right). The red and blue circles label the parities (±) for the bulk bands at the M and L points. The band topology of the α-phase is estimated to be a normal insulator (NI). c, Projected bulk bands for the top surface (001) of α-Bi4I4. The colour of the lines denotes different kz values.
