Quasi-periodic flat-band model constructed by molecular-orbital representation

We construct a tight-binding model that hosts both a quasi-periodic nature and macroscopic degenerate zero-energy modes. The model can be regarded as a counterpart of the Aubry–André–Harper (AAH) model, which is a paradigmatic example of the quasi-periodic tight-binding model. Our main focus is on the many-body state where the flat-band-like degenerate zero-energy modes are fully occupied. We find a characteristic sublattice dependence of the particle density distribution. Further, by analyzing the hyperuniformity of the particle density distribution, we find that it belongs to the class-I hyperuniform distribution, regardless of the model parameter. We also show that, upon changing the parameter, the finite-energy modes exhibit the same extended-to-localized transition as that for the original AAH model.