Structure of the quasi-one-dimensional Si(553)-Au surface
Structure of the quasi-one-dimensional Si(553)-Au surface
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准一维Si(553)-Au表面结构
DOI：
10.1103/physrevb.82.075426
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
and H. Sugiyama
中科院分区：
文献类型：
--
作者：
W. Voegeli;T. Takayama;T. Shirasawa;M. Abe;K. Kubo;T. Takahashi;K. Akimoto;and H. Sugiyama
Si(553)-Au表面由周期性的单台阶和(111)阶梯组成，具有准一维电子结构。本文报道了用X射线衍射法测定该表面的原子结构。用X射线荧光光谱仪测得金的覆盖率为0.5单分子层，即每个原始单位晶胞有两个金原子。由X射线衍射强度直接建立了结构模型，并逐步建立了结构模型。首先，从Patterson图中得到金原子的相对位置。利用金原子的位置，计算了Patterson图的反卷积，确定了金原子相对于衬底的位置。最后，用迭代的相位和幅度恢复算法重建了电子密度，得到了硅原子在表面的位置。用这种方法得到的结构模型的主要特征是在表面最顶层的(111)阶梯上有一排金二聚体，在台阶边缘附近有一条蜂窝状的硅原子链。用实验衍射数据对该模型进行结构修正，得到合理的原子位置和原子值为3.35，优于以往的模型。该模型与Krawiec[Phys.版本B 81,115436(2010年)]10.1103/PhysRevB.81.115436，但没有强调制。
The Si(553)-Au surface consists of a periodic array of single steps and (111) terraces with a quasi-one-dimensional electronic structure. In this paper, the determination of the atomic structure of this surface with x-ray diffraction is reported. The gold coverage of the surface was measured to be 0.5 monolayer using x-ray fluorescence spectroscopy, i.e., two gold atoms per primitive unit cell. A structural model was constructed directly from the x-ray diffraction intensities with a step-by-step approach. First, the relative positions of the gold atoms were obtained from the Patterson map. Using the positions of the gold atoms, the deconvolution of the Patterson map was calculated and the positions of the gold atoms relative to the substrate were determined. Finally, the positions of the silicon atoms at the surface were obtained from a reconstruction of the electron density with an iterative phase and amplitude recovery algorithm. The main features of the structural model obtained in this way are a row of gold dimers on the (111) terraces in the topmost layer of the surface, and a honeycomb chain of silicon atoms near the step edge. Structural refinement of this model with the experimental diffraction data gave reasonable atomic positions and avalue of 3.35, better than previous models. The model is related to themodel recently proposed by Krawiec [Phys. Rev. B 81, 115436 (2010)]10.1103/PhysRevB.81.115436 but without the strongmodulation.