PhysRevLett.91.025505.pdf (293.8 kB)
Metastable Frenkel pair defect in graphite: source of Wigner energy?
journal contribution
posted on 2023-06-08, 04:44 authored by M I Heggie, C P Ewels, R H Telling, A A El-Barbary, P R BriddonThe atomic processes associated with energy storage and release in irradiated graphite have long been subject to untested speculation. We examine structures and recombination routes for interstitial-vacancy (I-V) pairs in graphite. Interaction results in the formation of a new metastable defect (an intimate I-V pair) or a Stone-Wales defect. The intimate I-V pair, although 2.9 eV more stable than its isolated constituents, still has a formation energy of 10.8 eV. The barrier to recombination to perfect graphite is calculated to be 1.3 eV, consistent with the experimental first Wigner energy release peak at 1.38 eV. We expect similar defects to form in carbon nanostructures such as nanotubes, nested fullerenes, and onions under irradiation.
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Journal
Physical Review LettersISSN
0031-9007Publisher
American Physical SocietyExternal DOI
Issue
2Volume
91Page range
025505Department affiliated with
- Chemistry Publications
Notes
MIH directed the work in his group and co-authored the paper. Briddon credited for use of his code (AIMPRO). First explanation of the micro structural changes that store and release energy and identification of the metastable Frenkel pair. Quantitative activation barrier in exact agreement with experiment.Full text available
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Legacy Posted Date
2012-02-06First Open Access (FOA) Date
2016-03-22First Compliant Deposit (FCD) Date
2016-08-17Usage metrics
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