Ion-beam channeling yields of host and impurity atoms inLiNbO3: Computer simulations

Abstract

A Monte Carlo program for the simulation of channeling phenomena in ${\mathrm{LiNbO}}_{3}$ crystals is described. Results of the program are compared with experimental yields for Nb, Li, and O from angular scans through the 〈0001〉, 〈022\ifmmode\bar\else\textasciimacron\fi{}1〉, 〈04\ifmmode\bar\else\textasciimacron\fi{}41〉, and 〈112\ifmmode\bar\else\textasciimacron\fi{}0〉 axial directions and through the (0001) planar direction obtained with 1.6-MeV ${\mathrm{He}}^{+}$ and proton beams. A set of calculated angular scans for different axial and planar directions, and different impurity locations in ${\mathrm{LiNbO}}_{3}$, is presented. The program has been applied to identify the lattice location of Nd, Eu, and Hf in ${\mathrm{LiNbO}}_{3}$, and that of Lu and Hf in Mg-doped ${\mathrm{LiNbO}}_{3}$ by comparing the experimental data with the simulated angular scans. The results confirm that the Hf atoms occupy substitutional Li sites and Eu and Nd atoms lie at a position shifted by \ensuremath{\approxeq}0.4 \AA{} from the regular Li site along the c axis and towards the nearest oxygen plane in ${\mathrm{LiNbO}}_{3}$. The Hf and Lu atoms occupy the Nb and Li sites respectively if the ${\mathrm{LiNbO}}_{3}$ is codoped with Mg atoms.