Simple analytical embedded-atom-potential model including a long-range force for fcc metals and their alloys.

Centre of Instrumental Analysis, Wuhan University, Wuhan 430072, China~Received 19 October 1995; revised manuscript received 4 March 1996!A simple analytical embedded-atom method~EAM! model is developed. The model includes a long-rangeforce. In this model, the electron-density function is taken as a decreasing exponential function, the two-bodypotential is defined as a function like a form given by Roseet al. @Phys. Rev. B 33, 7983 ~1986!#, and theembedding energy is assumed to be an universal form recently suggested by Banerjea and Smith. The embed-ding energy has a positive curvature. The model is applied to seven fcc metals ~Al, Ag, Au, Cu, Ni, Pd, and Pt!and their binary alloys. All the considered properties, whether for pure metal systems or for alloy systems, arepredicted to be satisfactory at least qualitatively. The model resolves the problems of Johnson’s model forpredicting the properties of the alloys involving metal Pd. However, more importantly, ~i! by investigating thestructure stability of seven fcc metals using the present model, we found that the stability energy is dominatedby both the embedding energy and the pair potential for fcc-bcc stability while the pair potential dominates andis underestimated for fcc-hcp stability; and~ii! we find that the predicted total energy as a function of latticeparameter is in good agreement with the equation of state of Rose et al. for all seven fcc metals, and that thisagreement is closely related to the electron density, i.e., the lower the contribution from atoms of the second-nearest neighbor to host density, the better the agreement becomes. We conclude the following: ~i! for anEAM, where angle force is not considered, the long-range force is necessary for a prediction of the structurestability; or ~ii! the dependence of the electron density on angle should be considered so as to improve thestructure-stability energy. The conclusions are valid for all EAM models where an angle force is not consid-ered. @S0163-1829~96!07727-2#I. INTRODUCTION