| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Energetics of He and H Atoms in W–Ta Alloys: First-Principle Calculations |
| Chu-Bin Wan**, Su-Ye Yu, Xin Ju** |
Department of Physics, University of Science and Technology Beijing, Beijing 100083
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| Cite this article: |
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Chu-Bin Wan, Su-Ye Yu, Xin Ju 2018 Chin. Phys. Lett. 35 047102 |
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Abstract Properties of various defects of He and H atoms in W–Ta alloys are investigated based on density functional theory. The tetrahedral interstitial site is the most configured site for self-interstitial He and H in W and W–Ta alloys. Only a single He atom favors a substitutional site in the presence of a nearby vacancy. However, in the coexistence of He and H atoms in the presence of the vacancy, the single H atom favors the tetrahedral interstitial site (TIS) closest to the vacancy, and the He atom takes the vacancy center. The addition of Ta can reduce the formation energy of TIS He or H defects. The substituted Ta affects the charge density distribution in the vicinity of the He atom and decreases the valence electron density of the H atoms. A strong hybridization of the H $s$ states and the nearest W $d$ state s exists in W$_{53}$He$_{1}$H$_{1}$ structure. The sequence of the He $p$ projected DOS at the Fermi energy level is in agreement with the order of the formation energy of the He–H pair in the systems.
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Received: 18 January 2018
Published: 13 March 2018
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| PACS: |
71.15.Mb
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(Density functional theory, local density approximation, gradient and other corrections)
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61.82.Bg
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(Metals and alloys)
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71.15.Pd
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(Molecular dynamics calculations (Car-Parrinello) and other numerical simulations)
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61.80.Lj
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(Atom and molecule irradiation effects)
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| Fund: Supported by the National Natural Science Foundation of China under Grant No 11605007, and the Funding from the China Scholarship Council under Grant No 201506465019. |
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