论文标题
量子旋转厅边缘状态和层间耦合在扭曲的双层wte $ _2 $
Quantum spin Hall edge states and interlayer coupling in twisted-bilayer WTe$_2$
论文作者
论文摘要
最近在过渡金属二色氏元基因（TMD）wte $ _2 $的单层中证明了以拓扑保护的自旋偏好边缘状态为特征的量子自旋大厅（QSH）效应。但是，这种拓扑保护的鲁棒性在很大程度上尚未探索，该异质结构包含一个或多个QSH绝缘体。在这项工作中，我们使用扫描隧道显微镜和光谱法（STM/STS）来探索扭曲的双层（TBL）WTE $ _2 $的拓扑性质，该性质是由折叠单层产生的，以及撕裂堆放的制造。在TBL双层边缘，我们观察到QSH边缘状态的特征光谱特征，在拓扑学上繁殖的Asly BiLayer中不存在。对于小扭曲角，矩形的莫伊尔图案会形成，从而导致频带结构的局部修改。使用第一原理计算，我们将tbl wte $ _2 $及其拓扑边缘状态的相互作用量化为层间距离的函数，并得出结论，可以通过扭转角度以及层间相互作用来调整wte $ _2 $ biyers的拓扑。
The quantum spin Hall (QSH) effect, characterized by topologically protected spin-polarized edge states, was recently demonstrated in monolayers of the transition metal dichalcogenide (TMD) WTe$_2$. However, the robustness of this topological protection remains largely unexplored in van der Waals heterostructures containing one or more layers of a QSH insulator. In this work, we use scanning tunneling microscopy and spectroscopy (STM/STS) to explore the topological nature of twisted bilayer (tBL) WTe$_2$ which is produce from folded monolayers, as well as, tear-and-stack fabrication. At the tBL bilayer edge, we observe the characteristic spectroscopic signature of the QSH edge state that is absent in topologically trivial as-grown bilayer. For small twist angles, a rectangular moiré pattern develops, which results in local modifications of the band structure. Using first principles calculations, we quantify the interactions in tBL WTe$_2$ and its topological edge states as function of interlayer distance and conclude that it is possible to tune the topology of WTe$_2$ bilayers via the twist angle as well as interlayer interactions.
