Computer-simulation studies of extrinsic defects inLiNbO3crystals

In this paper we report our results of atomistic-simulation studies concerning the incorporation of impurity ions into ${\mathrm{LiNbO}}_3$ crystals. We show that the incorporation of impurity ions into the ${\mathrm{LiNbO}}_3$ lattice must involve intrinsic defects, which result mainly from the observed ${\mathrm{Li}}_2$O deficiency in ${\mathrm{LiNbO}}_3$ crystals. Divalent and also trivalent ions are predicted to substitute intrinsically present ${\mathrm{Nb}}_{\mathrm{Li}}$-antisite defects; i.e., these impurities will finally occupy Li sites. For ${\mathrm{Mg}}^{2+}$ incorporation we are able to compare calculated solution mechanisms with experimentally obtained results.