6533b7dcfe1ef96bd127283a

RESEARCH PRODUCT

Si29Hyperfine Structure of theE′αCenter in Amorphous Silicon Dioxide

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We report a study by electron paramagnetic resonance on the $E^{\ensuremath{'}}{}_{\ensuremath{\alpha}}$ point defect in amorphous silicon dioxide ($a\mathrm{\text{\ensuremath{-}}}{\mathrm{SiO}}_{2}$). Our experiments were performed on $\ensuremath{\gamma}$-ray irradiated oxygen-deficient materials and pointed out that the $^{29}\mathrm{Si}$ hyperfine structure of the $E^{\ensuremath{'}}{}_{\ensuremath{\alpha}}$ consists of a pair of lines split by $\ensuremath{\sim}49\text{ }\text{ }\mathrm{mT}$. On the basis of the experimental results, a microscopic model is proposed for the $E^{\ensuremath{'}}{}_{\ensuremath{\alpha}}$ center, consisting of a hole trapped in an oxygen vacancy with the unpaired electron $s{p}^{3}$ orbital pointing away from the vacancy in a back-projected configuration and interacting with an extra oxygen atom of the $a\mathrm{\text{\ensuremath{-}}}{\mathrm{SiO}}_{2}$ matrix.