Elastic interaction of defects on crystal surfaces

Surface defects corresponding to adatoms, vacancies and steps interact, aff ecting and often dominating kinetic processes associated with thin-film gro wth. A discrete harmonic model for the evaluation of the interaction energy between surface defects is presented. It is based on the concept of eigens trains and allows for the accurate evaluation of the elastic field, both at the immediate vicinity of the defects, as well as in the farfield. Results for the interaction energy suggest conditions for which a body-centered-cu bic crystal surface will grow in a stable, two-dimensional, step-flow mode. In order to verify the accuracy of the discrete elastic model, we present results of atomic simulations that incorporate Embedded Atom Method (EAM) p otentials. The discrete elastic model results compare favorably with result s from our atomic EAM simulations and agree with the far-field predictions of continuum elastic theory.