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Proceedings Paper

Theoretical study of structural and optical properties of F-centers in tetragonal BaTiO3
Author(s): Henry Pinto; Simon Elliott; Arvids Stashans
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Paper Abstract

Using the density functional theory (DFT) within the local density approximation (LDA) and a method based on the Hartree-Fock (HF) approximation, we study the structural, electronic and optical properties of F-centers (two electrons in an oxygen-vacancy) in the tetragonal lattice of the perovskite-type BaTiO3 crystal. In this structure the F-center has two non-equivalent positions due to the two different O atoms; namely, the F-center situated in the Ti-O-Ti chains along the [001] polarization axes (Va0) and the F-center situated in the Ti-O-Ti chains within the x-y plane (Vb0). Both cases are considered in our study. The obtained results point out that the crystal structure containing Va0 center is energetically more stable than that of the Vb0) center. The two electrons of the F-center are found to be localized on the two adjacent Ti ions and their ground state is composed mainly of Ti 3dz2 atomic orbital. Besides, we have computed the allowed optical transitions for the F-center using the so-called ΔSCF method. As a result the obtained absorption energies are found to be equal to 1.47 eV for the Va0 center as well as 3.07 and 4.27 eV for the Vb0 center.

Paper Details

Date Published: 8 August 2003
PDF: 7 pages
Proc. SPIE 5122, Advanced Organic and Inorganic Optical Materials, (8 August 2003); doi: 10.1117/12.515781
Show Author Affiliations
Henry Pinto, Univ. College Cork (Ireland)
Corp. de Fisica Fundamental y Aplicada (Ecuador)
Simon Elliott, Univ. College Cork (Ireland)
Arvids Stashans, Corp. de Fisica Fundamental y Aplicada (Ecuador)


Published in SPIE Proceedings Vol. 5122:
Advanced Organic and Inorganic Optical Materials

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