Theoretical studies of EPR spectra and defect structure for Er3+ center in lithium niobate

The optical and EPR spectra of octahedral Er3+ center in LiNbO3 have been studied by diagonalizing 364 × 364 complete energy matrices. The new set of crystal-field parameters that can well account for the Stark levels and EPR parameters have been obtained for Er3+ ions in LiNbO3. Simultaneously, by simulating the most reliable six-order parameter B60 obtained, we have presented the evidence that the Er3+ ions do not occupy the actual Li+ site, but have a displacement along the C3-axis away from the Li+ center by about 0.0454 nm. The conclusion is well in accord with that drawn by earlier workers.