Quantum spin Hall (QSH) effect is an intriguing phenomenon arising from the helical edge states in two-dimensional topological insulators. We use molecular beam epitaxy (MBE) to prepare FeSe films with atomically sharp nematic domain boundaries, where tensile strains, nematicity suppression, and topological band inversion are simultaneously achieved. Using scanning tunneling microscopy (STM), we observe edge states at the Fermi level that spatially distribute as two distinct strips in the vicinity of the domain boundaries. At the end point of the boundaries, a bound state at the Fermi level is further observed. The topological origin of the edge states is supported by density functional theory calculations. Our findings not only demonstrate a candidate for QSH states but also provide a new pathway to realize topological superconductivity in a single-component film.

中文翻译：

---

FeSe薄膜中向列畴壁的边缘状态

量子自旋霍尔（QSH）效应是二维拓扑绝缘体中由螺旋边缘状态引起的有趣现象。我们使用分子束外延（MBE）制备具有原子锐利的向列域边界的FeSe薄膜，其中可以同时实现拉伸应变，向列性抑制和拓扑带反转。使用扫描隧道显微镜（STM），我们观察到了费米能级的边缘状态，这些状态在空间边界附近以两个不同的条带空间分布。在边界的终点，进一步观察到费米能级的束缚态。边缘态的拓扑起源由密度泛函理论计算支持。