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| 基于Kekulé晶格非厄米系统拓扑边缘态的研究 |
| Research on topological edge state in a non-Hermitian system based on the Kekulé lattice |
| 投稿时间：2022-07-13 |
| DOI：10.3969/j.issn.1005-5630.2023.003.001 |
| 中文关键词: Kekulé晶格 非厄米系统 拓扑边缘态 狄拉克点 |
| 英文关键词:Kekulé lattice non-Hermitian system topological edge state Dirac point |
| 基金项目:国家自然科学基金 （62271320） |
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| 摘要点击次数: 1954 |
| 全文下载次数: 1624 |
| 中文摘要: |
| 基于Kekulé晶格，验证了物质拓扑相与晶格原子间耦合作用之间的关系，研究了非厄米效应对拓扑绝缘体的影响。设计了两种格点增益损耗分布方式，分别说明了不同增益损耗对体态能谱、边缘态能谱的影响。随着增益损耗值的增大，体态能谱和边缘态能谱将经历能带间隙减小，能带在临界值处关闭形成狄拉克点，随后狄拉克点劈裂形成一对奇异点的过程。区别于传统对Kekulé晶格的研究，在保持系统胞内耦合作用相同的基础上，将胞间耦合作用分化为水平方向和垂直方向的两个量，分别进行调控，验证了拓扑边缘态能谱中能带间隙的有无不仅与几何边界相关，也受系统胞间耦合相互作用的调控。 |
| 英文摘要: |
| The relationship between the topological phase of matter and interactions of the system was confirmed for the Kekulé lattice. The impact of non-Hermitian effect on topological insulator was investigated. Two types of gain and loss configurations were designed to illustrate their effects on bulk energy spectra and edge energy spectra. It is found that the bandgap decreases with the increase of the gain and loss, and is eventually closed and forms a non-Hermiticity-induced Dirac point. Finally, the Dirac point splits into a pair of singular points. Distinguishing from traditional Kekulé lattice, intercellular coupling is differentiated into horizontal and vertical dimensions for independent control based on the same intracellular coupling. This approach verifies that the gapless edge mode is not only related to geometric boundary, but also regulated by the intercellular coupling of the system. |
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