Calculations of F centers in KNbO3 ferroelectric crystals

R. I. Eglitis; Eugene A. Kotomin

doi:10.1117/12.266526

Calculations of F centers in KNbO₃ ferroelectric crystals

Laboratory of Computer Modeling of Electronic Structure of Solids, Institute of Solid State Physics
Laboratory of Kinetics in Self-Organizing Systems, Institute of Solid State Physics

Osnabrück University

Research output: Contribution to journal › Conference article › peer-review

4 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	150-152
Number of pages	3
Journal	Proceedings of SPIE - The International Society for Optical Engineering
Volume	2967
DOIs	https://doi.org/10.1117/12.266526
Publication status	Published - 1997
Event	Optical Inorganic Dielectric Materials and Devices - Riga, Latvia Duration: 26 Aug 1996 → 26 Aug 1996

Keywords

Ferroelectrics
INDO
Optical properties
Semi-empirical calculations
Supercell model

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10.1117/12.266526

Cite this

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title = "Calculations of F centers in KNbO3 ferroelectric crystals",

abstract = "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.",

keywords = "Ferroelectrics, INDO, Optical properties, Semi-empirical calculations, Supercell model",

author = "Eglitis, \{R. I.\} and Kotomin, \{Eugene A.\}",

year = "1997",

doi = "10.1117/12.266526",

language = "English",

volume = "2967",

pages = "150--152",

journal = "Proceedings of SPIE - The International Society for Optical Engineering",

issn = "0277-786X",

publisher = "SPIE",

note = "Optical Inorganic Dielectric Materials and Devices ; Conference date: 26-08-1996 Through 26-08-1996",

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TY - JOUR

T1 - Calculations of F centers in KNbO3 ferroelectric crystals

AU - Eglitis, R. I.

AU - Kotomin, Eugene A.

PY - 1997

Y1 - 1997

N2 - 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.

AB - 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.

KW - Ferroelectrics

KW - INDO

KW - Optical properties

KW - Semi-empirical calculations

KW - Supercell model

UR - https://www.scopus.com/pages/publications/58049148112

U2 - 10.1117/12.266526

DO - 10.1117/12.266526

M3 - Conference article

AN - SCOPUS:58049148112

SN - 0277-786X

VL - 2967

SP - 150

EP - 152

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

T2 - Optical Inorganic Dielectric Materials and Devices

Y2 - 26 August 1996 through 26 August 1996

ER -

Calculations of F centers in KNbO₃ ferroelectric crystals

Abstract

Keywords

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