Calculation of the surface segregation of Ni-Cu alloys with the use of the embedded-atom method

The surface composition of Ni-Cu alloys has been calculated as a function of atomic layer, crystal face, and bulk composition at a temperature of 800 K. The results show that the composition varies nonmonotonically near the surface with the surface layer strongly enriched in Cu while the near-surface layers are enriched in Ni. The calculations use the embedded-atom method [M. S. Daw and M. I. Baskes, Phys. Rev. B 29, 6443 (1984)] in conjunction with Monte Carlo computer simulations. The embedding functions and pair interactions needed to describe Ni-Cu alloys are developed and applied to the calculation of bulk energies, lattice constants, and short-range order. The heats of segregation are computed for the dilute limit, and the composition profile is obtained for the (100), (110), and (111) surfaces for a variety of bulk compositions. The results are found to be in accord with experimental data.