单层
材料科学
结晶学
X射线光电子能谱
散射
衍射
格子(音乐)
分析化学(期刊)
锰
晶格常数
扩展X射线吸收精细结构
晶体结构
Atom(片上系统)
化学
吸收光谱法
核磁共振
光学
纳米技术
物理
嵌入式系统
冶金
色谱法
计算机科学
声学
作者
Philippe Schieffer,Marie-Christine Hanf,C. Krembel,M.-H. Tuilier,G. Gewinner,D. Chandesris
标识
DOI:10.1142/s0218625x97001620
摘要
Mn films with a thickness of one monolayer have been deposited, in ultrahigh vacuum, on a Ag (100) single crystal at room temperature, and analyzed by X-ray photoelectron diffraction (XPD) and surface extended X-ray absorption fine structure (SEXAFS). The strong enhancement of the X-ray photoelectron Mn2p 3/2 signal along the Ag[1100] direction indicates that a substantial fraction of the Mn atoms is located within the second topmost atomic layer. The SEXAFS data demonstrate that the Mn – Ag and Mn – Mn first neighbor distances are the same as the Ag – Ag distances in the Ag lattice; as a result, the atoms occupy Ag sites on the fcc lattice. Comparison of the experimental data with FEFF calculations indicates that a superficial Mn – Ag alloy is formed. If the film is mildly (330 K) annealed, the contrast in the XPD Mn 2p 3/2 modulations versus polar angle increases and reaches a maximum value of 60%. As confirmed by single scattering simulations, these results mean that atomic place exchange occurs between Mn and Ag atoms, and eventually the second atomic plane of the sample is constituted mainly by Mn atoms, whereas the first atomic layer is a pure Ag plane, i.e. a buried atomic Mn monolayer is formed.
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