Epitaxial growth of Al9Ir2 intermetallic compound on Al(100): Mechanism and interface structure
| Autor: | M.-C. de Weerd, Sašo Šturm, Emilie Gaudry, Joris Kadok, B. Ambrožič, Julian Ledieu, Katariina Pussi, Vincent Fournée |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Low-energy electron diffraction Structure (category theory) Intermetallic 02 engineering and technology 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences law.invention Condensed Matter::Materials Science Crystallography law 0103 physical sciences General Materials Science Density functional theory Scanning tunneling microscope 010306 general physics 0210 nano-technology |
| Zdroj: | Physical Review Materials. 2 |
| ISSN: | 2475-9953 |
| DOI: | 10.1103/physrevmaterials.2.043405 |
| Popis: | The adsorption of Ir adatoms on Al(100) has been investigated under various exposures and temperature conditions. The experimental and theoretical results reveal a diffusion of Ir adatoms within the Al(100) surface selvedge already at 300 K. Above 593 K, two domains of a $(\sqrt{5}\ifmmode\times\else\texttimes\fi{}\sqrt{5})R26.{6}^{\ensuremath{\circ}}$ phase are identified by low energy electron diffraction (LEED) and scanning tunneling microscopy measurements. This phase corresponds to the initial growth of an ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ compound at the Al(100) surface. The ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ intermetallic domains are terminated by bulklike pure Al layers. The structural stability of ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$(001) grown on Al(100) has been analyzed by density functional theory based calculations. Dynamical LEED analysis is consistent with an Ir adsorption leading to the growth of an ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ intermetallic compound. We propose that the epitaxial relationship ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}(001)\ensuremath{\parallel}\mathrm{Al}$(100) and ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}[100]\ensuremath{\parallel}\mathrm{Al}[031]/[013]$ originates from a matching of Al atomic arrangements present both on Al(100) and on pure Al(001) layers present in the ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ compound. Finally, the interface between ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ precipitates and the Al matrix has been characterized by transmission electron microscopy measurements. The cross-sectional observations are consistent with the formation of ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$(001) compounds. These measurements indicate an important Ir diffusion within Al(100) near the surface region. The coherent interface between ${\mathrm{Al}}_{9}{\mathrm{Ir}}_{2}$ and the Al matrix is sharp. |
| Databáze: | OpenAIRE |
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