Multiple scattering theory was used to study the effect of adding Cu upon the driving force for the electromigration of Al adatoms on a (111) Al surface. The theory involved a computational framework which combined layer Korringa-Kohn–Rostoker calculations with coherent potential approximations in order to describe carrier scattering by a compositionally disordered overlayer. An investigation was made of how the substitution of Cu for Al adatoms, in the disordered overlayer, altered the average effective wind valence of Al and Cu adatoms within the overlayer. For adatom coverages of less than about 0.2, it was found that the effect of Cu substitution was to reduce the magnitude of the average effective wind valence of Al adatoms by about 0.4%/Cu at 273K.

Driving Force for Adatom Electromigration within Mixed Cu/Al Overlayers on Al(111). P.J.Rous: Journal of Applied Physics, 2001, 89[9], 4809-14