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Unusual Multilayer Surface Alloy: Al(100)-c(2 x 2)-2Li
A Mikkelsen1, M Borg, J H Petersen
1Institute of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark.
Physical Review Letters
|September 5, 2001
Summary
A new multilayer surface alloy of lithium (Li) on aluminum (Al) was discovered. This unusual structure, confirmed by calculations, mimics a known alloy type and suggests a similar surface structure for bulk Al(3)Li.
Area of Science:
- Materials Science
- Surface Science
- Condensed Matter Physics
Background:
- Surface alloys offer unique properties compared to bulk materials.
- Understanding the atomic arrangement of surface alloys is crucial for their application.
Purpose of the Study:
- To investigate the structure of a lithium-monolayer on aluminum (100) surface.
- To determine the stoichiometry and atomic arrangement of the resulting surface alloy.
Main Methods:
- Low Energy Electron Diffraction (LEED) was used to analyze the surface structure.
- Total-energy calculations were performed to confirm experimental findings and predict bulk properties.
Main Results:
- A distinct multilayer surface alloy formed, comprising alternating Al-Li and pure Al layers.
- The observed layer stoichiometry matches the (100) surface of the metastable Al(3)Li bulk alloy.
- The relative orientation of Al-Li layers resembles the Al(3)Ti-type structure.
Conclusions:
- The adsorption of Li on Al(100) results in a complex, ordered surface alloy.
- Experimental and computational results suggest a faulted, Al(3)Ti-type surface for bulk Al(3)Li.