论文标题

呼吸kagome晶格的角落模式:起源和鲁棒性

Corner modes of the breathing kagome lattice: origin and robustness

论文作者

Herrera, M. A. J., Kempkes, S. N., de Paz, M. Blanco, Swart, A. García-Etxarri I., Smith, C. Morais, Bercioux, D.

论文摘要

我们研究二维呼吸kagome晶格的非平凡阶段,显示边缘和角模式。二维薄片的角局部模式最初被识别为高阶拓扑阶段的标志,但后来证明对被认为可以保护它们的扰动是微不足道的。使用各种理论和仿真技术,我们确认它不会显示高阶拓扑:角模式具有微不足道的性质。然而,它们可能受到保护。首先,我们在一个紧密的结合模型中显示了一组扰动,该模型可以将角模式从零能量移开,还可以重复一些用于表明模式微不足道的扰动。此外,我们更详细地分析了角模式的保护,并发现只涉及符合sublatice或概括的手性和晶体对称性的扰动以及晶格连接性,将角模式固定在零能量上。破坏性干扰模型证实了结果。最后,我们分析了大量呼吸kagome晶格的松饼键模型。使用拓扑和对称标记,例如Wilson环和拓扑量子化学,我们将两个呼吸阶段确定为绝素断开的不同阻塞的原子限制。

We study the non-trivial phase of the two-dimensional breathing kagome lattice, displaying both edge and corner modes. The corner localized modes of a two-dimensional flake were initially identified as a signature of a higher-order topological phase but later shown to be trivial for perturbations that were thought to protect them. Using various theoretical and simulation techniques, we confirm that it does not display higher-order topology: the corner modes are of trivial nature. Nevertheless, they might be protected. First, we show a set of perturbations within a tight-binding model that can move the corner modes away from zero energy, also repeat some perturbations that were used to show that the modes are trivial. In addition, we analyze the protection of the corner modes in more detail and find that only perturbations respecting the sublattice or generalized chiral and crystalline symmetries, and the lattice connectivity, pin the corner modes to zero energy robustly. A destructive interference model corroborates the results. Finally, we analyze a muffin-tin model for the bulk breathing kagome lattice. Using topological and symmetry markers, such as Wilson loops and Topological Quantum Chemistry, we identify the two breathing phases as adiabatically disconnected different obstructed atomic limits.

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