Agenda

Résumé : In between the periodic systems and random systems, there is an intermediate system so-called quasiperiodic system. These systems do not have periodicity but possess long-range orders. Recently, these systems are attracting attention, because many fascinating phenomena including unconventional superconductivity have been reported by experimental groups. In addition, there is a special system called quasicrystal. These systems possess both quasiperiodicity and crystalline nature. In Ref. (1), we combined a typical model of topological charge pumping (Rice-Mele model) and Fibonacci quasicrystal to make the Fibonacci-Rice-Mele model which possesses topological charge pumping while conserving quasicrystalline nature. Since this model is quasicrystal, the lattice also has a fractal structure. Accompanying this nature, the electronic band structure has fractal energy gaps, and we can induce and characterize multilevel topological charge pumping.
(1) M. Yoshii, S. Kitamura and T. Morimoto, Phys. Rev. B 104, 155126 (2021).