Ab initio study of stability and migration of H and He in hcp-Sc
Ab initio calculations based on density functional theory have been performed to determine the relative stabilities and migration of H and He atoms in hcp-Sc. The results show that the formation energy of an interstitial H or He atom is smaller than that of a corresponding substitutional atom. The tetrahedral (T) interstitial position is more stable than an octahedral (O) position for both He and H interstitials. The nudged elastic band method has been used to study the migration of interstitial H and He atomss in hcp-Sc. It is found that the migration energy barriers for H interstitials in hcp-Sc are significantly different from those for He interstitials, but that their migration mechanisms are similar. In addition, the formation energies of five different configurations of a He-He pair were determined, revealing that the most stable configuration consists of two He atoms located at the second-neighbor tetrahedral interstitial sites along the c axis. The formation and relative stabilities of some small He clusters have also been investigated.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1004803
- Report Number(s):
- PNNL-SA-76726; AT6020100
- Journal Information:
- Journal of Physics. Condensed Matter, 23(3):035701, Journal Name: Journal of Physics. Condensed Matter, 23(3):035701 Journal Issue: 3 Vol. 23; ISSN 0953-8984; ISSN JCOMEL
- Country of Publication:
- United States
- Language:
- English
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