As a heavy analog of graphene, plumbene is a two-dimensional material with strong spin-orbit coupling effects. Using scanning tunneling microscopy, we observe that Pb forms a flat honeycomb lattice on an Fe monolayer on Ir(111). In contrast, without the Fe layer, a $c(2\times 4)$ structure of Pb on Ir(111) is found. We use density-functional theory calculations to rationalize these findings and analyze the impact of the hybridization on the plumbene band structure. In the unoccupied states the splitting of the Dirac cone by spin-orbit interaction is clearly observed, while the occupied Pb states are strongly hybridized with the substrate. In a freestanding plumbene we find a band inversion below the Fermi level that leads to the formation of a topologically nontrivial gap. Exchange splitting as mediated by the strong hybridization with the Fe layer drives a quantum spin Hall to quantum anomalous Hall state transition.

中文翻译：

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磁性基板上的铅：扫描隧道显微镜和密度泛函理论的组合研究

作为石墨烯的重类似物，铅是具有强自旋轨道耦合效应的二维材料。使用扫描隧道显微镜，我们观察到Pb在Ir（111）的Fe单层上形成了扁平的蜂窝状晶格。相反，如果没有铁层，$C（2\times 4）$发现了Ir（111）上Pb的结构。我们使用密度泛函理论计算来合理化这些发现，并分析杂化对铅带结构的影响。在未占据状态下，可以清楚地观察到狄拉克锥通过自旋-轨道相互作用而分裂，而被占据的Pb状态则与底物强烈杂交。在一个独立的铅管中，我们发现在费米能级以下的能带反转会导致拓扑上不平凡的间隙的形成。与Fe层的强杂化介导的交换分裂驱动量子自旋霍尔跃迁至量子异常霍尔态跃迁。