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Atomistic calculations of elastic properties of metallic fcc crystal surfaces

Physical Review B · 2005 · 702 citations · 31 references

TL;DR

Elastic properties of crystal surfaces are useful in understanding mechanical properties of nanostructures. The study presents a fully nonlinear treatment of surface stress and surface elastic constants and develops a method to determine surface elastic properties from atomistic simulations. The method is illustrated on several fcc metal crystal faces using embedded atom potentials and outlines a possible experimental approach to determine surface elastic constants. The study finds that accounting for strain‑induced surface atom relaxations is crucial, as they do not alter surface stress but significantly affect surface elastic constants, and neglecting them can produce elastic constant values that are both incorrect in magnitude and sign.

Abstract

Elastic properties of crystal surfaces are useful in understanding mechanical properties of nanostructures. This paper presents a fully nonlinear treatment of surface stress and surface elastic constants. A method for the determination of surface elastic properties from atomistic simulations is developed. This method is illustrated with examples of several crystal faces of some fcc metals modeled with embedded atom potentials. The key finding in this study is the importance of accounting for the additional relaxations of atoms at the crystal surface due to strain. Although these relaxations do not affect the values of surface stress (as had been determined in previous works), they have a profound effect on the surface elastic constants. Failure to account for these relaxations can lead to values of elastic constants that are incorrect not only in magnitude but also in sign. A possible method for the experimental determination of the surface elastic constants is outlined.