Computer Modeling of Point Defects, Impurity Self-Ordering Effects and Surfaces in Advanced Perovskite Ferroelectrics
Abstract
The calculated optical properties of basic point defects - F-type centers and hole polarons - in KNbO_3 perovskite crystals are used for the interpretation of available experimental data. The results of quantum chemical calculations for perovskite KNb_xTa_(1-x)O_3 solid solutions are presented for x=0, 0.125, 0.25, 0.75, and 1. An analysis of the optimized atomic and electronic structure clearly demonstrates that several nearest Nb atoms substituting for Ta in KTaO_3 - unlike Ta impurities in KNbO_3 - reveal a self-ordering effect, which probably triggers the ferroelectricity observed in KNb_xTa_(1-x)O_3. Lastly, the (110) surface relaxations are calculated for SrTiO_3 and BaTiO_3 perovskites. The positions of atoms in 16 near-surface layers placed atop a slab of rigid ions are optimized using the classical shell model. Strong surface rumpling and surface-induced dipole moments perpendicular to the surface are predicted for both the O-terminated and Ti-terminated surfaces.
Additional Information
© 2000 Polish Physical Society. E.A.K. was partly supported by the Latvian National Programme on Micro and Optoelectronics and by the DAAD. G.B. and R.E. thank the Deutsche Forschungsgemeinschaft for financial support within the SFB 225. The authors are indebted to A.V. Postnikov, A.M. Stoneham and O.F. Schirmer for many stimulating discussions.Attached Files
Published - a098z5p03.pdf
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Additional details
- Eprint ID
- 80026
- Resolver ID
- CaltechAUTHORS:20170809-140804980
- Latvian National Programme on Micro and Optoelectronics
- Deutscher Akademischer Austauschdienst (DAAD)
- Deutsche Forschungsgemeinschaft (DFG)
- SFB 225
- Created
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2017-08-09Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field