发表机构
University of Rostock; Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area; Ocean University of China; University of Zanjan（罗斯托克大学; 粤港澳大湾区量子科学中心; 中国海洋大学; 赞詹大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究理论探究含非互易Rashba自旋轨道耦合的三聚化Su–Schrieffer–Heeger链，推导相边界闭式表达式，建立体边对应关系，为实现自旋分辨非厄米拓扑提供最小平台。
AI 中文摘要
我们从理论上研究了一种一维三聚化Su–Schrieffer–Heeger链，该链的每个单胞包含三个子晶格，且受到非互易Rashba自旋轨道耦合的作用。利用自旋翻转对称性，非厄米哈密顿量可分解为两个独立的自旋扇区，从而能够对非厄米皮肤效应和系统对称性进行自旋分辨分析。我们确定了包含四个体态相和两个边缘态相的丰富相图。体态相包括完全$\textit{PT}$未破缺（实谱）和完全反$\textit{PT}$未破缺（虚谱）区域，以及两个混合相，其中一个能带保持在实轴或虚轴上，另外两个能带形成复共轭对。两个边缘态相对应的拓扑边缘模式具有$\textit{PT}$未破缺（实）或反$\textit{PT}$未破缺（虚）能量。利用非布洛赫带理论和卡尔达诺方法，我们推导了相边界的闭式表达式，并为每个自旋扇区建立了体边对应关系。贝里相位和方向逆参与率的计算证实了我们的分析预测。我们的结果为实现自旋分辨非厄米拓扑和边缘选择性对称性保持提供了一个最小平台，其中体态和边缘态属于不同的对称性类别。
英文摘要
We theoretically investigate a one-dimensional trimerized Su--Schrieffer--Heeger chain with three sublattices per unit cell subjected to a nonreciprocal Rashba spin-orbit coupling. Invoking a spin-flip symmetry, the non-Hermitian Hamiltonian decomposes into two independent spin sectors, enabling a spin-resolved analysis of non-Hermitian skin effects and system symmetries. We identify a rich phase diagram consisting of four bulk phases and two edge-state phases. The bulk phases include fully $\mathcal{PT}$-unbroken (real-spectrum) and fully anti-$\mathcal{PT}$-unbroken (imaginary-spectrum) regimes, as well as two mixed phases where one band remains on the real or imaginary axis while the other two form complex-conjugate pairs. The two edge-state phases correspond to topological edge modes with either $\mathcal{PT}$-unbroken (real) or anti-$\mathcal{PT}$-unbroken (imaginary) energies. Using non-Bloch band theory and Cardano's method, we derive closed-form expressions for phase boundaries and establish the bulk-edge correspondence for each spin sector. Calculations of Berry phase and directional inverse participation ratios confirm our analytical predictions. Our results provide a minimal platform for realizing spin-resolved non-Hermitian topology and edge-selective symmetry preservation, in which the bulk and edge states belong to distinct symmetry classes.
Comments17 pages, 7 figures
