Threshold displacement energies and defect formation energies in Y2Ti2O7
Journal Article
·
· Journal of Physics: Condensed Matter
- Pacific Northwest National Laboratory (PNNL)
- ORNL
Ab initio molecular dynamics simulations have been carried out to determine the threshold displacement energies Ed and the corresponding defect configurations, and ab initio methods have been used to accurately determine their formation energies in Y2Ti2O7. The minimum Ed is found to be 27 eV for a Y recoil along the <100> direction, 31.5 eV for Ti atoms along the <100> direction, 14.5 eV for O48f atoms along the <110> direction and 13 eV for O8b atoms along the <111> direction. The average Ed value determined is 32.7, 34.2, 14.2 and 16.1 eV for yttrium, titanium, O48f and O8b atoms, respectively. Cation interstitials at vacant 8a sites, which are generally occupied by oxygen anions, and at the bridge sites between two neighboring cations along the <010> direction are observed after low energy recoil events. A systematic study of defect formation energies suggests that cation interstitials, which are located at 8a sites and bridge sites along the <010> direction, and in split configurations along the <010>, <110> or <111> direction, are all stable with low defect formation energies. It is suggested that the relative stability of cation interstitials may provide a pathway of driving ion-irradiation induced amorphization in Y2Ti2O7.
- Research Organization:
- Oak Ridge National Laboratory (ORNL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 992100
- Journal Information:
- Journal of Physics: Condensed Matter, Journal Name: Journal of Physics: Condensed Matter Journal Issue: 41 Vol. 22; ISSN 0953-8984; ISSN 1361-648X
- Country of Publication:
- United States
- Language:
- English
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