Tunable caging of excitation in decorated Lieb-ladder geometry with long-range connectivity

Abstract

Controlled Aharonov–Bohm caging of wave train is reported in a quasi-one-dimensional version of Lieb geometry with next-nearest-neighbor hopping integral within the tight-binding framework. This longer-wavelength fluctuation is considered by incorporating periodic, quasi-periodic or fractal kind of geometry inside the skeleton of the original network. This invites exotic eigenspectrum displaying a distribution of flat band states. Also a subtle modulation of external magnetic flux leads to a comprehensive control over those non-resonant modes. Real space renormalization group method provides us an exact analytical prescription for the study of such tunable imprisonment of excitation. The non-trivial tunability of external agent is important as well as challenging in the context of experimental perspective.