A computational study of intrinsic and extrinsic defects in LiNbO₃

Abstract

Lithium niobate is a material with many important technological applications as a result of its diverse physical properties. Using a recently derived interatomic potential, intrinsic defect energies have been calculated leading to conclusions about the defect properties of the material that are compared with experimental conclusions. The incorporation of dopant ions into the structure is also considered, and solution energies are calculated, which enable predictions to be made about which ions are most easily added and which solution energy schemes are favoured energetically.

Growth, defect structure, and THz application of stoichiometric lithium niobate

“…139 Based on the new potentials, formation energies of intrinsic defects in LiNbO 3 , such as vacancies, cation interstitials at structural vacancies (i.e., in empty oxygen octahedra), Frenkel and Schottky defects, were determined. 162,163 Subsequently, three reactions were separately investigated, where the antisite niobium was compensated by lithium or niobium vacancies and the interstitial niobium by lithium vacancies…”

Optical properties of Pr and Eu-doped SrAl12O19: A theoretical study

“…SrAl 12 O 19 was modelled using the potential derived by Rezende et al [10], and the structure determined by Lindop et al [8]. The potentials for the trivalent rare earth ion-oxygen interactions were obtained from Araujo et al [11]. Calculations of rare earth doping were performed using the Mott-Littleton method [12] in which atoms in a spherical region immediately surrounding the defect are treated explicitly, and a continuum approach is used for more distant regions of the lattice.…”

EXAFS simulations in Zn-doped LiNbO3based on defect calculations

“…The details of the defect modelling calculations were described in previous papers [1], [2], [3] and the potential sets and defect configurations for the Zn ions in the LiNbO 3 matrix were the ones described by the Araujo, RM at al. [3].…”

“…The next step was the inclusion of the charge compensation that, as discussed earlier, is important in the case of LiNbO 3 defects. The first attempt would be to include the simplest possible charge compensating that is a Li vacancy, although the defect simulations presented in ref [2] did show that this is not the defect with the lower solution energy. One can argue that since the concentration of Zn in the samples measured in ref [5] is low, the Zn ions should be far apart from each other and the neutral defect that would keep the Zn isolated is the !"…”

“…LiNbO 3 has been modelled in both pure and undoped states ( [1], [2], [3]), and the calculations predict that Zn will substitute on the Li and Nb sites, with the defect 3 !" − !"…”