CNR-Istituto di Struttura della Materia, via Fosso del Cavaliere 100, 00133 Rome, Italy and European Theoretical Spectroscopy Facility (ETSF) and Dipartimento di Fisica, Università di Roma "Tor Vergata," Via della Ricerca Scientifica 1, 00133 Roma, Italy.
Phys Rev Lett. 2013 Aug 23;111(8):087401. doi: 10.1103/PhysRevLett.111.087401. Epub 2013 Aug 22.
The intensively studied Si(111)-(5×2)-Au surface is reexamined using reflectance anisotropy spectroscopy and density functional theory simulations. We identify distinctive spectral features relating directly to local structural motifs such as Si honeycomb chains and atomic gold wires that are commonly found on Au-reconstructed vicinal Si(111) surfaces. Optical signatures of chain dimerization, responsible for the observed (×2) periodicity, are identified. The optical response, together with STM simulations and first-principles total-energy calculations, exclude the new structure proposed very recently based on the reflection high-energy electron diffraction technique analysis of Abukawa and Nishigaya [Phys. Rev. Lett. 110, 036102 (2013)] and provide strong support for the Si honeycomb chain with the triple Au chain model of Erwin et al. [Phys. Rev. B 80, 155409 (2009)]. This is a promising approach for screening possible models of complex anisotropic surface structures.
使用反射各向异性光谱和密度泛函理论模拟，我们重新研究了经过深入研究的 Si(111)-(5×2)-Au 表面。我们确定了与局部结构基元（如 Si 蜂窝链和常见于 Au 重构的 Si(111)倾斜表面的原子金丝）直接相关的独特光谱特征。确定了负责观察到的（×2）周期性的链二聚体的光学特征。光学响应以及 STM 模拟和第一性原理总能量计算，排除了最近基于 Abukawa 和 Nishigaya [Phys. Rev. Lett. 110, 036102 (2013)] 的反射高能电子衍射技术分析提出的新结构，并为 Erwin 等人提出的 Si 蜂窝链与三倍 Au 链模型[Phys. Rev. B 80, 155409 (2009)]提供了有力支持。这是筛选复杂各向异性表面结构的可能模型的一种很有前途的方法。
