Formation and migration of helium pair in bcc Fe from first principle calculations
Formation and migration of helium pair in bcc Fe from first principle calculations
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根据第一原理计算，bcc Fe 中氦对的形成和迁移
DOI：
10.1016/j.commatsci.2019.109192
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发表时间：
2019
影响因子：
3.3
通讯作者：
Qian Guian
中科院分区：
文献类型：
--
作者：
Li Liuliu;Shi Jingyi;Peng Lei;Jiang Wei;Qian Guian
用第一性原理方法研究了bcc Fe晶体中两个He原子的能量学和构型。如果初始He-He距离小于2.82 Å，两个间隙He原子将结合成氦对。从形成能分解分析中我们发现，两个He原子配对会减少He与Fe基体之间的界面，从而减轻He-1s和Fe-3d轨道的扰动。作为形成能的主导部分，两个近He原子引起的电子变差能小于两个远He原子引起的电子变差能，这是两个近He原子之间结合的原因。此外，利用He-He地层能量超曲面研究了氦对沿[1 0 0]方向的迁移。通过与微推弹性带计算的比较，发现这种特殊的能量超表面能有效地揭示金属中氦对的迁移。
We investigated the energetics and configurations of two interstitial He atoms in bcc Fe crystal using first-principle method. Two interstitial He atoms will bind together as helium pair if the initial He-He distance is less than 2.82 Å. From a formation energy decomposing analysis we found that, pairing of two He atoms would reduce the interface between He and Fe matrix which mitigates the perturbation of He-1s and Fe-3d orbitals. As a dominant part of the fomation energy, the electron variation energy caused by two close He atoms is less than that of two far He atoms, which accounts for the reason of binding between two close He atoms. Besides, the migration of helium pair along direction [1 0 0] was investigated by a He-He formation energy hypersurface. Through the comparison with Nudged Elastic Band calculation, it’s found that this special energy hypersurface was effective in revealing the migration of helium pair in metals.