Epitaxial growth of BP-like Bi(110) with moiré pattern and potential topological edge state
Epitaxial growth of BP-like Bi(110) with moiré pattern and potential topological edge state
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DOI：
10.1016/j.apsusc.2023.157596
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发表时间：
2023-05
影响因子：
6.7
通讯作者：
Yun-liang Wang;Yechan Song;Limei Wang;Limin She;Weifeng Zhang
中科院分区：
文献类型：
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作者：
Yun-liang Wang;Yechan Song;Limei Wang;Limin She;Weifeng Zhang
类黑磷（BP-like） Bi（110）薄膜是一种具有非耗散拓扑边缘态的大带隙二维（2D）拓扑绝缘体（TI）候选者，近年来引起了人们的广泛关注。然而，具有大块带隙和拓扑边缘态的Bi（110）薄膜还没有得到明确的实验证实。在这里，高质量的bp样Bi（110）薄膜被外延生长在半导体SnSe衬底上。利用扫描隧道显微镜/光谱学（STM/S）确定了bp样结构，并对其电子结构进行了研究。此外，观察到明显的准平方莫尔条纹，并且在距离费米能较远的1BL - Bi（11 - 10）薄膜中，电子态在空间上受到莫尔条纹的显著调制；相反，费米能量附近的电子态受莫尔维尔模式的影响较小。重要的是，我们还观察到1BL和2BL Bi（110）薄膜边缘的态增强，特别是2BL薄膜，边缘态峰延伸至2nm深度的明显迹象，表明SnSe上2BL bp样Bi（110）是潜在的二维TI。因此，我们的研究为bp类Bi（110）薄膜的进一步拓扑研究提供了一个平台。
Black-phosphorus-like (BP-like) Bi(1 1 0) thin film, a potential large band gap two-dimensional (2D) topological insulator (TI) candidate that hosts a non-dissipative topological edge state, has attracted a lot of attention in recent years. However, the Bi(1 1 0) thin film with a large bulk band gap and topological edge states has not been definitely confirmed experimentally. Here, high-quality BP-like Bi(1 1 0) thin film is epitaxially grown on a semiconductor SnSe substrate. Employing scanning tunneling microscopy/spectroscopy (STM/S), the BP-like structure was determined, and the corresponding electronic structure was also investigated. In addition, a distinct quasi-squared moiré pattern was observed, and the electronic states far away from Fermi energy in the 1BL Bi(1 1 0) film are significantly modulated by the moiré pattern spatially; instead, the electronic states near the Fermi energy are less influenced by the moiré pattern. Importantly, we also observed the enhanced states at the edge of 1BL and 2BL Bi(1 1 0) films, especially for 2BL film, with a clear sign of edge state peak extending to 2 nm depth, suggesting that 2BL BP-like Bi(1 1 0) on SnSe is a potential 2D TI. As a result, our research provides a platform for the further topological investigation of the BP-like Bi(1 1 0) thin film.