Fig. 4: Topological flat bands and non-trivial Wyckoff positions of Wannier orbitals. | Light: Science & Applications

Fig. 4: Topological flat bands and non-trivial Wyckoff positions of Wannier orbitals.

From: Strong interlayer coupling and stable topological flat bands in twisted bilayer photonic Moiré superlattices

Fig. 4

a Eigenstates of the bulk (green), edge (blue), and corner (red) states in a finite size moiré superlattice (5 × 5 primitive unit cell). b Maximal Wyckoff positions and the mirror reflection symmetry in the unit cell. The dashed line represents the primitive unit cell. The rotational center of the twist corresponds to the Wyckoff position 2b. LSWs in the innermost dodecagonal quasi- atoms form OAL2b. c Energy eigenvalues in finite size systems. The red square and yellow circle represent the corner and edge states, respectively. Gray dots represent the bulk states. d Table representing the second Stiefel–Whitney number of each global band gap. The second Stiefel–Whitney number is determined by the number of the inversion-odd bands at the TRIM points

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