Molecular dynamics simulations have been used to study the mechanism of ion beam mixing in metal bilayers. We are able to explain the ion induced low-temperature phase stability, atomic mixing and melting behavior of bilayers using only a simple ballistic picture up to 10 keV ion energies. The atomic mass ratio of the overlayer and the substrate constituents seems to be a key quantity in understanding atomic mixing. This picture explains in a simple way ion beam mixing in a overwhelming number of miscible and immiscible bilayer systems up to high ion energies. Remarkably the existing experimental data follow the same trend as the simulated values. The critical bilayer mass ratio of δ≤0.33 is required for the occurrence of a thermal spike slocal meltingd with a lifetime of τ≤0.3 ps at low-energy ion irradiation (1 keV) due to a ballistic mechanism. These findings might be important in understanding the mechanism of ion induced phase evolution in solids and could improve the controlled fabrication of metal nanostructures.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Mar 15 2005|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics