LONG-RANGE ADATOM DIFFUSION MECHANISM ON FCC (100) EAM MODELED MATERIALS

A long range adatom diffusion mechanism has been observed in simulations on the fcc (100) surfaces of embedded atom method (EAM) modeled materials. This mechanism primarily involves the adatom and two atoms in the top substrate layer. After passing through the saddle configuration the adatom is found two rows down and one row over from its original position. The movement of the adatom is like that of a knight on a chess board. The activation barrier of this mechanism is high, and it begins to appear at temperatures about half the melting temperature of the material. Due to the long range nature of this mechanism it could significantly affect the adatom diffusion rate as compared to typical hopping between adjacent minima or diffusion via the exchange mechanism.