کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5420066 | 1507403 | 2009 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Nanostructure formation on Ir(1Â 0Â 0)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Nanostructure formation on Ir(1Â 0Â 0) Nanostructure formation on Ir(1Â 0Â 0)](/preview/png/5420066.png)
چکیده انگلیسی
As a structurally rather flexible surface Ir(1Â 0Â 0) can be prepared with different structural phases. The clean and stable phase, Ir(1Â 0Â 0)-(5Â ÃÂ 1)-hex, exhibits a quasi-hexagonal top layer arranged in 5-fold periodicity on the square substrate. Also, a hydrogen stabilized phase, Ir(1Â 0Â 0)-(5Â ÃÂ 1)-H, with Ir wires of single atomic width and again 5-fold periodicity residing on (1Â 0Â 0) layers below can be prepared as well as a bulk-like terminated but metastable phase, Ir(1Â 0Â 0)-(1Â ÃÂ 1). The (5Â ÃÂ 1) reconstructed phases offer linear adsorption channels of nanosized width, so that by deposition of other metals linear nanostructures can be formed by self-organisation in a bottom-up process. This is demonstrated for the deposition of the transition metals Fe, Co and Ni which, on the flat (1Â 0Â 0) surface, would be under considerable tensile strain of the order of 8-9%. We show that the accompanying stress leads to the formation of stair-rod dislocations by which the stress is relaxed. Calculations using density functional theory (DFT) reveal for the (1Ã1) phase as substrate that these dislocations appear at a coverage of about 3-4 monolayers and are either pinned by surface defects or by further adatoms which decorate them. On the (5Â ÃÂ 1)-H phase this pinning appears with long-range order. So, by the Ir wires at the interface the developing nanostructures including the dislocations can be structurally accessed by experiment, here with crystallographic precision by quantitative low-energy electron diffraction (LEED). Moreover, scanning tunneling microscopy (STM) reveals both the morphology of the nanostructured films and their buckling with atomic resolution.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Progress in Surface Science - Volume 84, Issues 1â2, March 2009, Pages 2-17
Journal: Progress in Surface Science - Volume 84, Issues 1â2, March 2009, Pages 2-17
نویسندگان
K. Heinz, L. Hammer,