First-principles study of the incorporation and diffusion of helium in cubic zirconia
First-principles study of the incorporation and diffusion of helium in cubic zirconia
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DOI：
10.1016/j.jnucmat.2011.06.025
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发表时间：
2010-12
影响因子：
3.1
通讯作者：
Peng Zhang;Yong Lu;Chaohui He;Ping Zhang
中科院分区：
文献类型：
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作者：
Peng Zhang;Yong Lu;Chaohui He;Ping Zhang
采用广义梯度近似(GGA)投影增广波(PAW)方法，用第一性原理总能量计算方法，研究了具有和不存在本征空位缺陷的立方ZrO2中氦(He)的掺入和扩散。通过从头计算确定了主要的缺陷，并了解了它们的电子性质。立方ZrO2中的本征氧间隙和氧空位均表现为负U行为。He杂质的掺入能表明，在热力学平衡浓度下，首先占据Zr空位是可取的，而固溶能表明，在热力学平衡浓度下，He将被安置在间隙位上。通过计算间隙扩散和空位辅助扩散所对应的He迁移能，我们认为它最有可能通过跳跃单个空位来扩散。值得注意的是，我们计算的He的空位辅助扩散能垒与实验测量结果符合得很好。
The incorporation and the diffusion of helium (He) with and without the intrinsic vacancy defects in the cubic ZrO2are investigated through the first-principles total-energy calculations, in which the projector-augmented-wave (PAW) method with the generalized gradient approximation (GGA) is adopted. Ab initio calculations are carried out to identify the dominant defects and understand their electronic properties as well. Both the intrinsic oxygen interstitials and the oxygen vacancies in the cubic ZrO2show the negative-U behavior. The incorporation energy of He impurity indicates that it is preferable to occupy the Zr vacancy at first, whereas the solution energy suggests that He would be accommodated in the interstitial site at the thermodynamic equilibrium concentration. By calculating the He migration energies corresponding to both the interstitial diffusion and the vacancy assisted diffusion, we suggest that it is most likely to diffuse by hopping through a single vacancy. Remarkably, our calculated vacancy-assisted diffusion energy barrier of He is consistent well with the experimental measurement.