The elastic response of a vacancy, in a semi-infinite face-centered cubic lattice with a free surface, was calculated by using a new multi-scale Green’s function method. The latter treated lattice distortion near to the vacancy (at the atomistic level) and the free surface (at the macroscopic continuum level) within the same formalism. The lattice was modeled by using the lattice statics Green’s function, that accounted fully for the discrete atomistic structure of the lattice and could economically model a large crystallite which contained a million atoms. The method was especially useful for modeling the elastic response of nanocrystals which contained point defects, and in which surfaces and interfaces played important roles. The method bridged the length scales by relating microscopic lattice distortion, near to a point defect, to measurable macroscopic parameters of the solid such as the strain and the displacement field at a free surface. By using the Cleri-Rosato interatomic potential, the lattice distortion, relaxation energy and relaxation volume due to a vacancy were calculated, in an otherwise perfect lattice, for a million-atom model which contained a free (100) surface. The calculated value of the relaxation volume was in excellent agreement with the observed value. Numerical results were also obtained for strain and displacement fields at the free surface, due to a vacancy, and for the interaction energy between a vacancy and the free surface in anisotropic semi-infinite Cu.

Multiscale Green’s-Function Method for Modeling Point Defects and Extended Defects in Anisotropic Solids - Application to a Vacancy and Free Surface in Copper. V.K.Tewary: Physical Review B, 2004, 69[9], 094109 (13pp)