Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024, China.
Sci Rep. 2012;2:861. doi: 10.1038/srep00861. Epub 2012 Nov 15.
Using ab initio methods, we have investigated the structures and stabilities of Si(N) clusters (N ≤ 24) on Ag(111) surface as the initial stage of silicene growth. Unlike the dome-shaped graphene clusters, Si clusters prefer nearly flat structures with low buckling, more stable than directly deposition of the 3D freestanding Si clusters on Ag surface. The p-d hybridization between Ag and Si is revealed as well as sp(2) characteristics in Si(N)@Ag(111). Three types of silicene superstructures on Ag(111) surface have been considered and the simulated STM images are compared with experimental observations. Molecular dynamic simulations show high thermal stability of silicene on Ag(111) surfaces, contrast to that on Rh(111). The present theoretical results constitute a comprehensive picture about the interaction mechanism of silicene on Ag(111) surface and explain the superiority of Ag substrate for silicene growth, which would be helpful for improving the experimentally epitaxial growth of silicene.
我们采用从头算方法研究了 Si(N) 团簇（N ≤ 24）在 Ag(111)表面上的结构和稳定性，这是硅烯生长的初始阶段。与穹顶形石墨烯团簇不同，Si 团簇更喜欢具有低屈曲的近平面结构，比直接在 Ag 表面上沉积 3D 自由 Si 团簇更稳定。Ag 和 Si 之间的 p-d 杂化以及 Si(N)@Ag(111)中的 sp(2)特征也被揭示出来。我们考虑了 Ag(111)表面上的三种类型的硅烯超结构，并将模拟的 STM 图像与实验观察结果进行了比较。分子动力学模拟表明硅烯在 Ag(111)表面上具有高热稳定性，这与 Rh(111)上的情况形成对比。本理论研究结果全面描述了硅烯在 Ag(111)表面上的相互作用机制，并解释了 Ag 衬底对于硅烯生长的优越性，这将有助于提高硅烯的实验外延生长。
