<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>Si</mml:mi><mml:mprescripts /><mml:none /><mml:mn>29</mml:mn></mml:mmultiscripts></mml:math>Hyperfine Structure of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>E</mml:mi><mml:none /><mml:mo>′</mml:mo><mml:mi>α</mml:mi><mml:none /></mml:mmultiscripts></mml:math>Center in Amorphous Silicon Dioxide

Buscarino, Gianpiero; Agnello, S.; Gelardi, F. M.

doi:10.1103/physrevlett.97.135502

Cited by 34 publications

(33 citation statements)

References 14 publications

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“…Experimental verification of these finding is difficult. We note that the ESR properties of E' k -configuration are consistent with those of the recently observed E' -center (31). The existence of backprojected configurations of E' -center has been suggested first in ref.…”

Section: Ecs Transactionssupporting

confidence: 74%

Positive and Negative Oxygen Vacancies in Amorphous Silica

et al. 2009

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We modeled all stable positive and negative charge states of oxygen vacancies originating from the neutral O 3 Si=Si O 3 defect in amorphous SiO 2 (a-SiO 2 ) using an embedded cluster method on a distribution of structural sites. For the first time, we predict the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO 2 and demonstrate that negatively charged vacancies serve as deep electron traps. The results demonstrate that oxygen vacancies can be responsible for both the electron and hole trapping in silica. We compare our findings with the previous calculations and with the recent experimental data.

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Section: Ecs Transactionssupporting

confidence: 74%

Positive and Negative Oxygen Vacancies in Amorphous Silica

et al. 2009

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“…The generally recognized experimental hyperfine splittings for E γ , E α and E δ are 42, 49 and 10 mT, respectively. [21][22][23] Electronic structure theory, especially density functional theory (DFT) methods, becomes very popular for modeling and understanding results from magnetic resonance experiments. One of the most important parameters in EPR experiments on paramagnetic systems is the isotropic (Fermi contact) hyperfine coupling constant, which describes the magnetic interaction between the nuclear and electronic spins under isotropic averaging conditions.…”

Section: Introductionmentioning

confidence: 99%

First principles study of oxygen vacancy defects in amorphous SiO2

2017

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The oxygen vacancy defects of amorphous SiO2 (a-SiO2) in different charge states are investigated by the periodic density functional theory. Five types of the positively charged configurations are obtained including the dimer, forward-oriented, puckered 4×, 5× and back-projected unpuckered configurations. The energy, geometry structure, spin density, Bader charge and Fermi contact are concerned for these systems. These defects can be regarded as the potential microscopic structures for the corresponding centers including Eα′, Eγ′ and Eδ′ in the electron paramagnetic resonance (EPR) experiments. Then, the charge-state transitions of these defects are investigated by intentionally adding one electron to the positively charged systems. For the dimer, puckered 4× and back-projected unpuckered configurations, all of the corresponding neutral species maintain their initial types of geometry structures. For the forward-oriented configurations, the corresponding neutral species transform into the structures of the divalent Si atom. The puckered 5× configurations have the most abundant neutral species: some of them could maintain its style of the puckered 5× configurations, and some collapse to the neutral dimer or forward-oriented configurations. The dimer configurations have the lowest thermodynamic charge-state levels, and the puckered 4× configurations have the highest thermodynamic charge-state levels among the five types of configurations. This work is of benefit to identifying and controlling the oxygen defects in a-SiO2.

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“…Another relevant point defect falling into the class of the so called E' family [1,2,4,[16][17][18][19] in a-SiO 2 is the E' α [1,4,[18][19][20]. In contrast with the E' γ center, very little was known about it for a long time.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast with the E' γ center, very little was known about it for a long time. Only recently it has been proven that its 29 Si hyperfine structure comprises a pair of EPR lines split by ~49 mT [18,19], suggesting that the E' α center consists in a positively charged oxygen vacancy with the unpaired electron Si-sp 3 orbital pointing away from the vacancy in a back-projected configuration and interacting with an extra O atom of the a-SiO 2 matrix, as shown in Fig. 1(b).…”

Section: Introductionmentioning

confidence: 99%

“…1(b). On the basis of this microscopic model, it is inferred that the unpaired electrons involved in E' γ and E' α centers are located on quite similar O≡Si [18,19] have provided fundamental information on the atomic scale structure of the E' α center, other relevant questions concerning this defect remain open. In particular, in spite of the key role played by a-SiO 2 in a wide variety of modern applications, the influence of the E' α center on the optical properties of this technologically relevant material has never been clarified.…”

Section: Introductionmentioning

confidence: 99%

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Optical absorption and electron paramagnetic resonance of theEα′center in amorphous silicon dioxide

et al. 2008

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We report a combined study by optical absorption (OA) and electron paramagnetic resonance (EPR) spectroscopy on the E' α point defect in amorphous silicon dioxide (a-SiO 2 ). This defect has been studied in β-ray irradiated and thermally treated oxygen-deficient a-SiO 2 materials. Our results have pointed out that the E' α center is responsible for an OA Gaussian band peaked at ~ 5.8 eV and having a full width at half maximum (FWHM) of ~ 0.6 eV. The estimated oscillator strength of the related electronic transition is ~ 0.14. Furthermore, we have found that this OA band is quite similar to that of the E' γ center induced in the same materials, indicating that the related electronic transitions involve states highly localized on a structure common to both defects: the O≡Si• moiety.

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Si29Hyperfine Structure of theE′αCenter in Amorphous Silicon Dioxide

Cited by 34 publications

References 14 publications

Positive and Negative Oxygen Vacancies in Amorphous Silica

Positive and Negative Oxygen Vacancies in Amorphous Silica

First principles study of oxygen vacancy defects in amorphous SiO2

Optical absorption and electron paramagnetic resonance of theEα′center in amorphous silicon dioxide

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