The ternary topological insulators Bi 2 Se 3 − x Te x have attracted a great deal of attention due to their exotic physical and chemical properties. While most of the studies focus on the properties of these ternary TIs, limited research was performed to investigate the dynamic atomic stack of its crystal structure. We prepared high-quality Bi 2 Se 3 − x Te x thin films on GaAs(111)B substrates using molecular beam epitaxy, characterized with Raman spectroscopy, x-ray diffraction and photoelectron spectroscopy. It is found that when Se is replaced by Te, the preferred substituting sites are the middle layer at 0 < x < 1, and this is also valid for Se substituting Te at 2 < x < 3. In the middle region, the substituting atoms prefer to go to the first and the fifth layer.

中文翻译：

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Bi 2 Se 3 − x Te x薄膜中Se和Te的位置偏好

三元拓扑绝缘子Bi 2 Se 3-x Te x由于其奇异的物理和化学特性而引起了极大的关注。虽然大多数研究集中在这些三元TI的特性上，但进行了有限的研究以研究其晶体结构的动态原子堆。我们使用分子束外延在GaAs（111）B衬底上制备了高质量的Bi 2 Se 3-x Te x薄膜，并利用拉曼光谱，X射线衍射和光电子能谱进行了表征。发现当Se被Te取代时，优选的取代位是0 <x <1的中间层，这对于Se取代2 <x <3的Se也是有效的。在中间区域，取代原子更喜欢去第一层和第五层。