A three-dimensional concurrent atomistic/continuum analysis of an epitaxially strained island.

A three-dimensional concurrent atomistic/continuum analysis is performed to study the stress distributions in an epitaxial island. The island and the adjacent substrate are modeled by the molecular dynamics method, and the surrounding zone is modeled by the finite element method in which the nonlinear elasticity is governed by the atomic potential. An overlapping zone is defined to be the location where the atomistic and continuum models exchange necessary material information. It is found that the nonlinear elasticity based on the atomic potential is required for a smooth stress transition in the overlapping zone, and that the linear elasticity assumption significantly overestimates the stress levels at moderate and high loading levels. The implications of the present results on surface roughening driven by strain energy are discussed. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]