STUDY OF DEFECT FORMATION IN MODELED LITHIUM NIOBATE CLUSTERS
In the framework of the semiclassical atomistic model, the processes of clustering in a crystal of lithium niobate (LiNbO<sub>3</sub>) were studied. A computer simulation of the energy-equilibrium cluster of a lithium niobate crystal (LiNbO<sub>3</sub>) based on oxygen octahedra was carried out. The study showed that there is a cluster size that has an optimum energy, that is, energetically advantageous, within which a certain structure is organized, tending to the structure of a congruent crystal. In this case, the random casting of ions into the center of the octahedron is energetically more favorable. And a cluster with a congruent ratio is optimal in energy for any casting method and the size of the model cluster. It was determined that a stoichiometric crystal cannot exist due to a loss of electroneutrality; therefore, it is possible to achieve the desired properties, including the photorefractive effect, by introducing various impurity ions. An example of an impurity ion was an ion with a charge of 3+.