Topological bounded corner states induced by long-range interactions in Kagome lattice

¹ Department of Applied Physics, East China Jiaotong University - Nanchang 330013, PRC
² School of Computer Science, Jiangxi University of Traditional Chinese Medicine - Nanchang 330004, PRC
³ Key Laboratory of Low- Dimensional Quantum Structures and Quantum Control of Ministry of Education, Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University - Changsha 410081, PRC

^(a) 2446@ecjtu.edu.cn
^(b) davidxu0816@163.com

Received: 13 July 2020
Accepted: 5 September 2020

Abstract

We theoretically studied the corner states in photonic Kagome lattice with long-range interactions. Literature has confirmed that such model supports zero-energy corner states and finite-energy corner states known as type-II corner states. In this paper, through careful research, we found that there is another new type of finite-energy corner state in this system. By using the approximation method, we realized that the addition of long-range interactions causes coupling between topological edge states, which in turn makes these finite-energy corner states split from the edge states. Moreover, these finite-energy corner states are not located on the corners, but around the corners. And they are immune to the disorder in coupling strengths. Thus we call them topological bounded corner states. Our work reveals a way to generate bounded corner states by the long-range interactions, which offers a way for designing novel bounded devices.