Electronic and structural characteristics of diffusion process in Fe/Al(001) and Al/Fe(001) systems

Abstract

Diffusion behaviors that occurred in the initial stage of Fe-Al multilayer fabrication were investigated using ab initio pseudopotential calculations. The hollow site was the most stable adsorption site on both Al(001) and Fe(001) surfaces and the calculated energy barriers for the surface diffusion were 0.89eV for Fe/Al(001) and 0.64eV for Al/Fe(001) systems. The energy barrier for,the incorporation of the Fe adatom into the Al substrate was calculated to be 0.38 eV and the energy gain of the system was 0.49 eV. A maximum charge depletion of 0.35 bohr(-3) and a maximum charge accumulation of 0.17 bohr-3 were found in the Fe-Al bonds. The Al adatom required relatively a large energy barrier, i.e., 0.99 eV, for its incorporation into the Fe substrate and the total energy of. the system was increased by 0.13 eV.