Embedded-atom method: Derivation and application to impurities, surfaces, and other defects in metals

TLDR

Hydrogen and surface defects cannot be treated with pair potentials, underscoring the need for a more sophisticated approach. The authors develop the embedded‑atom method based on density‑functional theory as a new means of calculating ground‑state properties of realistic metal systems. The method derives the total energy from embedding energy, yielding lattice constants, elastic constants, sublimation and vacancy energies, and uses semiempirical embedding energy and pair potentials for Ni and Pd to analyze surface energies, hydrogen migration and binding, and fracture. The agreement with experiment, applicability to practical problems, and simplicity make it an effective tool for atomistic studies of defects in metals. Published in *Phys.

Abstract

We develop the embedded-atom method [Phys. Rev. Lett. 50, 1285 (1983)], based on density-functional theory, as a new means of calculating ground-state properties of realistic metal systems. We derive an expression for the total energy of a metal using the embedding energy from which we obtain several ground-state properties, such as the lattice constant, elastic constants, sublimation energy, and vacancy-formation energy. We obtain the embedding energy and accompanying pair potentials semiempirically for Ni and Pd, and use these to treat several problems: surface energy and relaxation of the (100), (110), and (111) faces; properties of H in bulk metal (H migration, binding of H to vacancies, and lattice expansion in the hydride phase); binding site and adsorption energy of hydrogen on (100), (110), and (111) surfaces; and lastly, fracture of Ni and the effects of hydrogen on the fracture. We emphasize problems with hydrogen and with surfaces because none of these can be treated with pair potentials. The agreement with experiment, the applicability to practical problems, and the simplicity of the technique make it an effective tool for atomistic studies of defects in metals.