Fig. 1: One-dimensional partially flat bands and quasi-compact localized states.
From: Quasi-localization and Wannier obstruction in partially flat bands
a The band structure of a semi-infinite zigzag graphene nanoribbon. At zero energy, the partially flat band and ghost flat band are plotted by the red solid and gray dashed lines, respectively. b The semi-infinite zigzag graphene nanoribbon has an edge on the left-hand side. The quasi-compact localized state(Q-CLS) is drawn by a gray region. The amplitudes of the Q-CLS are denoted by the colored circles, whose size stands for the magnitude of the amplitude, while the color represents the sign. We have different Q-CLSs depending on the position of the vertex indicated by the red star symbol. c A linear combination of the Q-CLSs, resulting in a Bloch wave function, whose amplitudes are plotted in (d).
