氧或铜杂质对与氢共存的铯化表面功函数的影响:关于中性束注入系统负氢离子源的研究

IF 2.3 2区 物理与天体物理 Q1 NUCLEAR SCIENCE & TECHNOLOGY
Heng Li , Xin Zhang , Yuhong Xu , Guangjiu Lei , Sanqiu Liu , Katsuyoshi Tsumori , Haruhisa Nakano , Masaki Osakabe , Mitsutaka Isobe , Shoichi Okamura , Akihiro Shimizu , Kunihiro Ogawa , Hiromi Takahashi , Zilin Cui , Jun Hu , Yiqin Zhu , Xiaolong Li , Huaqing Zheng , Xiaoqiao Liu , Shaofei Geng , CFQS team
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引用次数: 0

摘要

本研究基于密度泛函理论(DFT)方法研究了氧和铜杂质对 Cs/H/Mo (001) 表面功函数的影响。首先,研究了 2/16 θ 杂质在 Cs0.5/H0.5/Mo (001) 表面的沉积(下标 0.5 代表 8/16 θ 覆盖率)。研究发现,铯层下的杂质沉积和氧杂质原子沉积以及高对称性配置都会降低表面系能。随着杂质覆盖率的增加,可以观察到覆盖率小于或等于 8/16 θ 的杂质沉积有效地降低了 Cs0.5/H0.5/Mo (001) 表面的功函数。然而,随着铯和氢覆盖率的增加,杂质不再能有效降低功函数。此外,当铯的覆盖率达到 16/16 θ 时,表面功函数接近铯金属表面的功函数。另一个重要发现是,当氧杂质沉积在 Cs0.5/H0.5/Mo (001) 表面的铯层之上时,表面功函数会降低。这一反常现象归因于氧杂质沉积造成的显著电荷极化。使用爬升图像点弹性带 (CI-NEB) 方法评估了杂质穿过致密铯层到达 Mo (001) 基底的迁移障碍。氧杂质倾向于以分子形式穿越铯层,面临的最小迁移势垒为 0.52 eV,而铜原子在穿越铯层时遇到的迁移势垒较低,为 0.09 eV。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Effect of oxygen or copper impurities on the work function of cesiated surfaces under co-existence with hydrogen: A study about negative hydrogen ion sources for neutral beam injection systems
This study investigates the effect of oxygen and copper impurities on the work function of the Cs/H/Mo (001) surface based on the Density Functional Theory (DFT) method. First, the deposition of 2/16 θ impurities on the Cs0.5/H0.5/Mo (001) surface (the subscript 0.5 represents 8/16 θ coverage) is studied. It is found that the deposition of impurities beneath the cesium layer and oxygen impurities as atoms, and in a high-symmetry configuration, both lower the surface system energy. As the impurity coverage increases, it is observed that impurity deposition with a coverage of less than or equal to 8/16 θ effectively reduces the work function of the Cs0.5/H0.5/Mo (001) surface. However, as the cesium and hydrogen coverage increases, the impurities are no longer effective at reducing the work function. Moreover, when the cesium coverage reaches 16/16 θ, the surface work function approaches that of a cesium metal surface. Another important discovery is that when oxygen impurities are deposited above the cesium layer on the Cs0.5/H0.5/Mo (001) surface, a reduction in the surface work function is observed. This anomalous phenomenon is attributed to significant charge polarization caused by the deposition of oxygen impurities. The migration barriers of impurities traversing the dense cesium layer to the Mo (001) substrate are evaluated using the climbing image nudged elastic band (CI-NEB) method. Oxygen impurities tend to traverse the cesium layer in molecular form, facing a minimum barrier of 0.52 eV, while copper atoms encounter a lower barrier of 0.09 eV when traversing the cesium layer.
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来源期刊
Nuclear Materials and Energy
Nuclear Materials and Energy Materials Science-Materials Science (miscellaneous)
CiteScore
3.70
自引率
15.40%
发文量
175
审稿时长
20 weeks
期刊介绍: The open-access journal Nuclear Materials and Energy is devoted to the growing field of research for material application in the production of nuclear energy. Nuclear Materials and Energy publishes original research articles of up to 6 pages in length.
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