Positron states at a lithium-adsorbed Al(100) surface: Two-component density functional theory simulation
Positron states at a lithium-adsorbed Al(100) surface: Two-component density functional theory simulation
复制标题
吸附锂的 Al(100) 表面的正电子态：二元密度泛函理论模拟
DOI：
10.1103/physrevb.91.115409
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发表时间：
2015
影响因子：
3.7
通讯作者：
Kazuyuki Watanabe
中科院分区：
文献类型：
--
作者：
S. Hagiwara;Chunping Hu;Kazuyuki Watanabe
The positron surface state and the energetics for positron reemission are investigated using two-component density functional theory (TC-DFT) in the projector augmented-wave framework. Trapping of positrons by the surface image potential and the effect of the positron band-shift energy in the surface region are appropriately described by the corrugated mirror model and the ramp potential, respectively, without empirical parameters. The results obtained for various physical quantities of positron states on a clean Al(100) surface, i.e., the affinity, work function, life-time, binding energy, and activation energy, are in good agreement with the experimental results. The positron states on Li-adsorbed Al(100) surfaces are highly dependent on the Li coverage. In particular, the work function of positronium negative ionsbecomes negative at low Li coverage, which indicates the possible emission offrom the adsorbed surface. The present study not only elucidates the key energetics that are responsible for positron reemission from the surface, but also emphasizes the excellent performance of TC-DFT for prediction of the positron state on real surfaces.
