EXAFS simulations in Zn-doped LiNbO3 based on defect calculations

[摘要] Lithium niobate, LiNbO3, is an important technological material with good electro-optic, acousto-optic, elasto-optic, piezoelectric and nonlinear properties. EXAFS on Zn-doped LiNbO3found 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 LiNbO3lattice. 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 LiNbO3matrix.

[发布机构] Department of Physics, Federal University of Sergipe, Sao Cristavao-SE, Brazil^1;School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire; ST5 5BG, United Kingdom^2;Department of Physics, University of California Santa Cruz, Santa Cruz; CA; 95064, United States^3

[关键词] Defect calculations;Defect production;Doped sample;Lithium niobate;Nonlinear properties;Strategy use;Zn-doped