We have utilized scanning tunneling microscopy and spectroscopy (STM/STS) as well as x-ray linear dichroism (XLD) along with DFT calculations to determine the structural and electronic changes of the gold-covered nonstoichiometric BiTe single crystal surface. XLD spectra supported by a numerical simulation of several configurations show that at low coverage (< 1.0 ML) gold forms insoluble islands, while for higher coverage (> 1.0 ML) mixing at the Au/BiTe interface may occur. For local electronic characterization around stand-alone Au islands, small coverages were selected for which the inter-island distance is large enough to avoid overlapping island-wide effects. STS spectra reveal that for small coverages the topological surface states (TSS) are preserved. However, at a distance of about 10 nm from an Au island, by approaching the islands, the electronic structure gradually changes. This is manifested by a gradual shift of the STS spectra to more negative energies with respect to the pristine surface. The results are discussed in view of possible Au-BiTe mixing, a local charge transfer and the presence of in-plane downward band bending.

中文翻译：

---

Bi2Te3拓扑绝缘体上生长的Au岛周围的面内能带弯曲效应

我们利用扫描隧道显微镜和光谱 (STM/STS) 以及 X 射线线性二色性 (XLD) 以及 DFT 计算来确定金覆盖的非化学计量 BiTe 单晶表面的结构和电子变化。由几种配置的数值模拟支持的 XLD 光谱表明，在低覆盖率 (< 1.0 ML) 下，金形成不溶岛，而在较高覆盖率 (> 1.0 ML) 下，Au/BiTe 界面可能会发生混合。对于独立金岛周围的局部电子表征，选择了小覆盖范围，其中岛间距离足够大，以避免重叠的全岛效应。 STS 光谱表明，对于小覆盖范围，拓扑表面态 (TSS) 得以保留。然而，在距Au岛约10nm的距离处，通过接近该岛，电子结构逐渐发生变化。这表现为相对于原始表面，STS 光谱逐渐转向更多负能量。考虑到可能的 Au-BiTe 混合、局部电荷转移和面内向下能带弯曲的存在，对结果进行了讨论。