Topological modes in one- and two-dimensional systems have been proposed for numerous applications utilizing their exotic electronic responses. The 1D, zero-energy, topologically protected end modes can be realized in structures implementing the Su–Schrieffer–Heeger (SSH) model. While the edge modes in the SSH model are at exactly the mid-gap energy, other paradigmatic 1D models such as trimer and coupled dimer chains have non-zero energy boundary states. However, these structures have not been realized in an atomically tuneable system that would allow explicit control of the edge modes. Here, we demonstrate atomically controlled trimer and coupled dimer chains realized using chlorine vacancies in the c(2 × 2) adsorption layer on Cu(100). This system allows wide tuneability of the domain wall modes that we experimentally demonstrate using low-temperature scanning tunneling microscopy (STM).

一维和二维系统中的拓扑模式已被提出利用其奇特的电子响应进行众多应用。一维，零能量，受拓扑保护的最终模式可以在实现Su–Schrieffer–Heeger（SSH）模型的结构中实现。虽然SSH模型中的边缘模式恰好处于中间能隙，但其他范式1D模型（例如三聚体和耦合二聚体链）具有非零能量边界状态。但是，这些结构尚未在允许原子模式显式控制的原子可调谐系统中实现。在这里，我们演示了使用Cu（100）的c（2×2）吸附层中的氯空位实现的原子控制的三聚体和偶合的二聚体链。