EXAFS simulations in Zn-doped LiNbO₃based on defect calculations

Abstract

Abstract. Lithium niobate, LiNbO 3 , is an important technological material with good electrooptic, acousto-optic, elasto-optic, piezoelectric and nonlinear properties. EXAFS on Zn-doped LiNbO 3 found strong evidences that Zn substitutes primarily at the Li site on highly doped samples. In this work the EXAFS results were revisited using a different approach where the models for simulating the EXAFS results were obtained from the output of defect calculations. The strategy uses the relaxed positions of the ions surrounding the dopants to generate a cluster from where the EXAFS oscillations can be calculated. The defect involves not only the Zn possible substitution at either Li or Nb sites but also the charge compensating defects, when needed. From previous defect modelling, a subset of defects was selected based on the energetics of the defect production in the LiNbO 3 lattice. From them, all possible clusters were generated and the simulated EXAFS were computed. The simulated EXAFS were them compared to available EXAFS results in the literature. Based on this comparison different models could be proposed to explain the behaviour of Zn in the LiNbO 3 matrix.

Computational modelling of intrinsic defects in the orthosilicates Y2SiO5 and Lu2SiO5

“…They are based on interatomic potentials and energy minimization of the lattice that represents a great gain in defect studies, although some optical and electronic properties are not accessible in this approach. The accuracy of methodology has been successfully testified by several works in literature [25][26][27][28][29][30][31][32]. They provide information to help experimental techniques, i.e.…”