Diffusion and growth of nickel, iron and magnesium adatoms on the aluminum truncated octahedron: A molecular dynamics simulation

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• 作者：Jianyu Yang^a ; ^{wangyuhu2001cn@yahoo.com.cn} ; Wangyu Hu^b ; ^{Wangyuhu2001@yahoo.com.cn} ; Yurong Wu^c ; Xiongying Dai^b
• 关键词：Structure of clusters ; Metals and alloys ; Growth from solid phases ; Diffusion ; Molecular dynamics
• 刊名：Surface Science
• 出版年：2012
• 期刊代码：104_00396028
• 类别：ch
• 出版时间：June, 2012
• 卷：606
• 期：11-12
• 页码：971-980
• 文件大小：2330 K

摘要

The structure of nickel (Ni), iron (Fe), and magnesium (Mg) adatoms on the aluminum (Al) truncated octahedron is studied using molecular dynamics and the analytic embedded atom method. First, the energy barriers of several typical diffusion processes of Ni, Fe, and Mg adatoms on the Al truncated octahedral cluster were calculated using the nudged elastic band method. The calculated energy barriers were found to be related to the surface energy and atomic radius of the adatom and substrate atom. The result shows that the incorporation of Ni and Fe atoms into Al core easily occurs, and the Mg atom should segregate at the surface of the Al cluster. Thus, the growth of Ni, Fe and Mg on the Al truncated octahedron with 1289 atoms was simulated at several temperatures. In the Ni-Al and Fe-Al cases, the core-shell structure was not obtained. For the Mg-Al system, a good Mg shell on the Al core was found at lower temperatures, and an almost perfect truncated octahedron with more Al shells emerged with an increase in temperature.