Modeling zero-field splitting parameters for dopant Mn ~(2+) and Fe ~(3+) ions in anatase TiO _2 crystal using superposition model analysis

摘要

The local environment around Fe ~(3+) and Mn ~(2+) ions doped into anatase TiO _2 crystal is investigated and interpretation of EPR data, suggesting remote charge compensation, is provided. Using superposition model, the zero-field splitting (ZFS) parameters are modeled for Fe ~(3+) and Mn ~(2+) at the substitutional Ti ~(4+) and interstitial sites (D _(2d)). Several approaches are used to match the modeled b20 ZFS parameter with experimental values and thus to discriminate between various structural models. Theoretical predictions of the b4q parameters are also provided and tentative matching with experimental data is considered. The feasible values of the structural distortion parameters are predicted. The uniqueness and thus reliability of the predicted ZFS and distortion parameters are discussed.