Abstract
This paper proposes a non-Hermitian asymmetric rhombic lattice which supports fully flat spectrum and Aharonov-Bohm caging formed by the oppositely oriented unidirectional couplings at the exceptional point. The localization area of excitation can be manipulated by the distribution of the gain and loss
Highlights
Flat bands, which are dispersionless and independent of momentum, have displayed many exotic properties during the past few decades [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]
We notice that the spectrum is fully constituted by the flat bands and the eigenstates are definitely compactly localized in each isolated trimer; the corresponding eigenstates of the asymmetric rhombic lattice are compactly localized in the related five sites centered at one site of sublattice A associated with two sites of sublattices B and C, respectively, in its two neighbor diamond plaquettes
We show that the wave function of the compact localized states (CLSs) is still unchanged in Figs. 2(c) and 2(d), but the number of the CLSs supported in the non-Hermitian asymmetric rhombic lattice reduces by one-half, which is a consequence of the two-state coalescence at the exceptional point (EP)
Summary
Flat bands, which are dispersionless and independent of momentum, have displayed many exotic properties during the past few decades [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]. The bipartite sublattice symmetry leads to the PT -symmetric flat bands in the non-Hermitian environments, and the corresponding compact localized states (CLSs) are nondiffracting and robust to disorders [35]. Under the non-Hermitian particle-hole symmetry with tunable gain and loss, flat bands in such a system are composed of photonic zero modes [36]. In the non-Hermitian systems, the CLSs excited at any position are observable with the existence of flat bands in a tectonic optical system under PT symmetry [38]. The asymmetric rhombic lattice possesses a spectrum fully consisting of flat bands under the destructive interference when each diamond plaquette encloses a half magnetic flux quantum. The proposed non-Hermitian rhombic lattice supports an entirely real spectrum as well as the Aharonov-Bohm caging; the. We systematically investigate the tunable localization dynamics in the non-Hermitian asymmetric rhombic lattice.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
