Parity-dependent skin effects and topological properties in the multilayer nonreciprocal Su–Schrieffer–Heeger structures

• Published in: Frontiers of physics 2024-06, Vol.19 (3), p.33204, Article 33204
• Main Authors: Li, Jia-Rui, Jiang, Cui, Su, Han, Qi, Di, Zhang, Lian-Lian, Gong, Wei-Jiang
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; Condensed Matter Physics; Couplings; Lattices; Molecular; Multilayers; Optical and Plasma Physics; Parity; Particle and Nuclear Physics; Phase transitions; Physics; Physics and Astronomy; Research Article; Skin; Skin effect; Topology
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-023-1350-y

We concentrate on the skin effects and topological properties in the multilayer non-Hermitian Su–Schrieffer–Heeger (SSH) structure, by taking into account the nonreciprocal couplings between the different sublattices in the unit cells. Following the detailed demonstration of the theoretical method, we find that in this system, the skin effects and topological phase transitions induced by nonreciprocal couplings display the apparent parity effect, following the increase of the layer number of this SSH structure. On the one hand, the skin effect is determined by the parity of the layer number of this SSH system, as well as the parity of the band index of the bulk states. On the other hand, for the topological edge modes, such an interesting parity effect can also be observed clearly. Next, when the parameter disorders are taken into account, the zero-energy edge modes in the odd-layer structures tend to be more robust, whereas the other edge modes are easy to be destroyed. In view of these results, it can be ascertained that the findings in this work promote to understand the influences of nonreciprocal couplings on the skin effects and topological properties in the multilayer SSH lattices.