Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics
We investigate the role of Fe in the electronic structure of ferroelectric LiNbO3 by density-functional theory calculations. We show that Fe2+ on the Li site (Fe2+Li) features a displacement opposite to the direction of spontaneous polarization and acts as a trigger for the bulk photovoltaic (PV) ef...
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| Format: | Article |
| Language: | English |
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Wiley
2016-01-01
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| Series: | Advances in Condensed Matter Physics |
| Online Access: | http://dx.doi.org/10.1155/2016/2943173 |
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| author | Yuji Noguchi Ryotaro Inoue Masaru Miyayama |
| author_facet | Yuji Noguchi Ryotaro Inoue Masaru Miyayama |
| author_sort | Yuji Noguchi |
| collection | DOAJ |
| description | We investigate the role of Fe in the electronic structure of ferroelectric LiNbO3 by density-functional theory calculations. We show that Fe2+ on the Li site (Fe2+Li) features a displacement opposite to the direction of spontaneous polarization and acts as a trigger for the bulk photovoltaic (PV) effect. In contrast to Fe3+ on the Li site that forms the defect states (1e, a, and 2e) below the conduction band minimum, the reduction from Fe3+ to Fe2+ accompanied by a lattice relaxation markedly lowers only the a state (dz2) owing to a strong orbital hybridization with Nb-4d. The a state of Fe2+Li provides the highest electron-occupied defect state in the middle of the band gap. A reduction treatment of Fe-LN is expected to increase the concentration of Fe2+ and therefore to enhance the PV effect under visible light illumination. |
| format | Article |
| id | doaj-art-4095700aae574816be68f8125a2e8ed8 |
| institution | Kabale University |
| issn | 1687-8108 1687-8124 |
| language | English |
| publishDate | 2016-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Condensed Matter Physics |
| spelling | doaj-art-4095700aae574816be68f8125a2e8ed82025-02-03T05:46:20ZengWileyAdvances in Condensed Matter Physics1687-81081687-81242016-01-01201610.1155/2016/29431732943173Electronic Origin of Defect States in Fe-Doped LiNbO3 FerroelectricsYuji Noguchi0Ryotaro Inoue1Masaru Miyayama2Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JapanDivision of Physics, Institute of Liberal Education, School of Medicine, Nihon University, 30-1 Ooyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, JapanDepartment of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, JapanWe investigate the role of Fe in the electronic structure of ferroelectric LiNbO3 by density-functional theory calculations. We show that Fe2+ on the Li site (Fe2+Li) features a displacement opposite to the direction of spontaneous polarization and acts as a trigger for the bulk photovoltaic (PV) effect. In contrast to Fe3+ on the Li site that forms the defect states (1e, a, and 2e) below the conduction band minimum, the reduction from Fe3+ to Fe2+ accompanied by a lattice relaxation markedly lowers only the a state (dz2) owing to a strong orbital hybridization with Nb-4d. The a state of Fe2+Li provides the highest electron-occupied defect state in the middle of the band gap. A reduction treatment of Fe-LN is expected to increase the concentration of Fe2+ and therefore to enhance the PV effect under visible light illumination.http://dx.doi.org/10.1155/2016/2943173 |
| spellingShingle | Yuji Noguchi Ryotaro Inoue Masaru Miyayama Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics Advances in Condensed Matter Physics |
| title | Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics |
| title_full | Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics |
| title_fullStr | Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics |
| title_full_unstemmed | Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics |
| title_short | Electronic Origin of Defect States in Fe-Doped LiNbO3 Ferroelectrics |
| title_sort | electronic origin of defect states in fe doped linbo3 ferroelectrics |
| url | http://dx.doi.org/10.1155/2016/2943173 |
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