Introducing a New d0 Sc3+ Asymmetric Ion for Functional Materials: Large Birefringence Enhancement by ScO6 in Ba3Sc2(BO3)4 |
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Authors: | Jingfang Zhou Prof Rukang Li |
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Institution: | Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190 P.R. China |
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Abstract: | Transition metal ions with d0 electronic states (Ti4+, Zr4+, Nb5+ and Ta5+) are widely investigated as functional materials. This work first illustrates that Sc3+ ion, long-time ignored, displays a second-order Jahn-Teller (SOJT) effect similar to asymmetric oxide-coordinated transition metal ions, thus providing a new ground to seek for asymmetric functional materials with enhanced performances. In Ba3Sc2(BO3)4, BO3 groups are parallelly arranged, satisfying the ideal arrangement to produce large birefringence. Importantly, distorted octahedral ScO6 with Sc3+ ion in its d0 electronic state enlarges birefringence unexpectedly up to 0.149 @ 550 nm, which is larger than previously reported borates containing solely BO3, even to B3O6 units. Subsequently, the SOJT influence of distorted ScO6 octahedra on birefringence is verified by a comparison between experimental data and theoretical calculations. In addition, Ba3Sc2(BO3)4 also displays a high transmittance in the range of 230 nm–3.5 μm with a UV cut-off wavelength at 198 nm and a large laser induced damage threshold (2.7 GW/cm2), comparable to α-BaB2O4. Above characteristics imply that the title compound may be a promising birefringent material. |
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Keywords: | d0 electronic state functional materials Sc3+ ion second-order Jahn-Teller effect large birefringence |
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