Surface segregation of the metal impurity to the (100) surface of fcc metals

The surface segregation energies for a single metal impurity to the ( 1 0 0) surface of nine fcc metals ( Cu, Ag, Au, Ni, Pd, Pt, Rh, Al and Ir) have been calculated using the MAEAM and molecular dynamics ( MD) simulation. The results show that the effect of the surface is down to the fourth-layer and an oscillatory or monotonic damping (|E-1| > |E-2| > |E-3| > |E-4|) phenomenon in segregation energy has been obtained. The absolute value of the segregation energy E-1 for a single impurity in the first atomic layer is much higher than that in the nether layers. Thus, whether the surface segregation will work or not is mainly determined by E-1 which is in good relation to the differences in surface energy between the impurity and host crystals Delta Q = Q(imp) - Q(hos). So we conclude that an impurity with lower surface energy will segregate to the surface of the host with higher surface energy.