Milton, Katherine L;
Durrant, Thomas R;
Cobos Freire, Teofilo;
Shluger, Alexander L;
(2023)
Difference in Structure and Electronic Properties of Oxygen Vacancies in α-Quartz and α-Cristobalite Phases of SiO2.
Materials
, 16
(4)
, Article 1382. 10.3390/ma16041382.
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Abstract
α-cristobalite (α-C) is a polymorph of silica, mainly found in space exploration and geochemistry research. Due to similar densities, α-C is often used as a proxy for amorphous SiO2, particularly in computer simulations of SiO2 surfaces and interfaces. However, little is known about the properties of α-C and its basic oxygen defects. Using density functional theory (DFT) simulations we provide a comprehensive report on the properties of perfect structure and oxygen vacancies in α-C. The calculated properties of α-C are compared with those of the better-characterized α-quartz (α-Q). Our results demonstrated that the positively charged O vacancy in α-C is most stable in the dimer configuration, in contrast to α-Q, which favors the puckered configuration. A back-projected configuration was also predicted in both polymorphs. We calculated the optical transition energies and isotropic hyperfine constants for O vacancies in both α-Q and α-C, and compared our findings with the results of previous studies and experiments. This work, thus, offers one of the first in-depth investigations of the properties of oxygen vacancies in α-C.
| Type: | Article |
|---|---|
| Title: | Difference in Structure and Electronic Properties of Oxygen Vacancies in α-Quartz and α-Cristobalite Phases of SiO2 |
| Location: | Switzerland |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3390/ma16041382 |
| Publisher version: | https://doi.org/10.3390/ma16041382 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | DFT, cristobalite, defects, silicon dioxide |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10165815 |
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