Open AccessTopological edge states controlled by next-nearest-neighbor coupling and Peierls phase in a P T-symmetric trimerized lattice
Author(s) -
Chuan-Xun Du,
Nan Xu,
Lei Du,
Yan Zhang,
Jin-Hui Wu
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.438779
Subject(s) - physics , lattice (music) , k nearest neighbors algorithm , condensed matter physics , coupling (piping) , topology (electrical circuits) , phase (matter) , phase transition , quantum mechanics , materials science , combinatorics , mathematics , artificial intelligence , computer science , acoustics , metallurgy
We study the topological features in a trimerized lattice of parity-time symmetry with comparable nearest-neighbor (NN) and next-nearest-neighbor (NNN) couplings as well as a Peierls phase. Eigen energies of four edge states in two bandgaps, of topological origin verified by the quantized total Zak phase, are surprisingly independent of the NNN coupling and the Peierls phase. Topological regions with respect to the intercell NN coupling, as the intracell NN coupling is fixed, can be extended with reinforced localization strengths for one pair of edge states but reduced with weakened localization strengths for the other pair of edge states, by increasing the NNN coupling. The partial overlapping between extended and reduced topological regions promises then a two-step phase transition of 'zero - two - four' edge states, viable to be periodically modulated by the Peierls phase.