  Modeling point defects at an atomic scale requires careful treatment of the
long-range atomic relaxations. This elastic field can strongly affect point
defect properties calculated in atomistic simulations because of the finite
size of the system under study. This is an important restriction for ab initio
methods which are limited to a few hundred atoms. We propose an original
approach coupling ab initio calculations and linear elasticity theory to obtain
the properties of an isolated point defect for reduced supercell sizes. The
reliability and benefit of our approach are demonstrated for three problematic
cases: the self-interstitial in zirconium, clusters of self-interstitials in
iron, and the neutral vacancy in silicon.
