| Автор | Y M Chang |
| Автор | T H Yeom |
| Автор | Y Y Yeung |
| Автор | C Rudowicz |
| Дата выпуска | 1993-08-23 |
| dc.description | The energy levels and wavefunctions including the two lowest-lying levels, namely <sup>4</sup>A<sub>2</sub> and <sub>a</sub><sup>2</sup>E, for which reliable experimental data exist for Cr<sup>3+</sup> ions at C<sub>3</sub> symmetry sites in LiNbO<sub>3</sub>, are calculated using the complete matrix diagonalization method within the 3d<sup>3</sup> configuration. The Hamiltonian considered includes the electrostatic term, the Trees correction, the spin-orbit interaction and the crystal-field interaction. The role of the additional low-symmetry crystal-field term B<sub>4</sub><sup>-3</sup>O<sub>4</sub><sup>-3</sup> (in the Stevens operator notation), neglected in the C<sub>3v</sub> approximation used so far in the literature, is studied. The superposition model is developed for 3d<sup>3</sup> ions at C<sub>3</sub> symmetry sites and applied to study the site occupancy of Cr<sup>3+</sup> in LiNbO<sub>3</sub>. Analysis of the optical data indicates that Cr<sup>3+</sup> ions substitute at Nb sites and Li sites simultaneously. The present considerations offer an improvement over the earlier approximations using C<sub>3v</sub> symmetry only. The zero-field splitting predicted by the crystal-field calculations for Cr<sup>3+</sup> at the Nb site matches the experimental value from EPR studies very well. This is contrary to the earlier prediction by the superposition model analysis of the spin-Hamiltonian parameters indicating that the zero-field splitting for Cr<sup>3+</sup> ions at Li sites matches the experimental zero-field splitting better than that for Cr<sup>3+</sup> at Nb sites. Since the present calculations involve fitting not only the zero-field splitting but also the energies of the <sub>a</sub><sup>2</sup>E state, the present predictions may be more reliable than the previous predictions. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Superposition model and crystal-field analysis of the <sup>4</sup>A<sub>2</sub> and <sub>a</sub><sup>2</sup>E states of Cr<sup>3+</sup> ions at C<sub>3</sub> sites in LiNbO<sub>3</sub> |
| Тип | paper |
| DOI | 10.1088/0953-8984/5/34/009 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 5 |
| Первая страница | 6221 |
| Последняя страница | 6230 |
| Аффилиация | Y M Chang; Dept. of Appl. Sci., City Polytech. of Hong Kong, Hong Kong |
| Аффилиация | T H Yeom; Dept. of Appl. Sci., City Polytech. of Hong Kong, Hong Kong |
| Аффилиация | Y Y Yeung; Dept. of Appl. Sci., City Polytech. of Hong Kong, Hong Kong |
| Аффилиация | C Rudowicz; Dept. of Appl. Sci., City Polytech. of Hong Kong, Hong Kong |
| Выпуск | 34 |
