4 February 1997 Calculations of F centers in KNbO3 ferroelectric crystals
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Proceedings Volume 2967, Optical Inorganic Dielectric Materials and Devices; (1997) https://doi.org/10.1117/12.266526
Event: International Conference on Advanced Optical Materials and Devices, 1996, Riga, Latvia
Semi-empirical method of the intermediate neglect of the differential overlap (INDO) combined with the supercell model is applied to the calculations of the F center optical properties in ferroelectric KNbO3 perovskite crystals. It is shown that two electrons of the defect are weakly localized inside the O vacancy, unlike similar defects in ionic alkali halides, but are considerably spread over two nearest Nb atoms. For the orthorhombic phase stable at room temperatures three absorption bands are predicted to be at 2.72 eV, 3.04 eV and 3.11 eV, respectively. The first energy is close to the band at 2.7 eV observed in electron- irradiated crystals. In the high temperature, cubic phase only two bands, 2.67 eV and 3.04 eV, are expected to arise due to higher local symmetry of the defect.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
R. I. Eglitis, R. I. Eglitis, Eugene A. Kotomin, Eugene A. Kotomin, "Calculations of F centers in KNbO3 ferroelectric crystals", Proc. SPIE 2967, Optical Inorganic Dielectric Materials and Devices, (4 February 1997); doi: 10.1117/12.266526; https://doi.org/10.1117/12.266526


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