Density Functional Theory Study on Ag Adsorption on MgF2(010) Surface

作者:Wang Li Ping; Han Pei De; Hao Yu Ying; Zhang Zhu Xia; Xu Bing She*
来源:Chemical Journal of Chinese Universities, 2012, 33(3): 569-574.
DOI:10.3969/j.issn.0251-0790.2012.03.026

摘要

Geometric and electronic structures of MgF2(010) surface were calculated by the ultra-soft pseudopotential plane wave method based on density functional theory( DFT). Furthermore, the adsorption of Ag on the surface was discussed. The results show that compared with MgF2 bulk, the band gap of MgF2(010) surface is narrowed by about 0.9 eV, the energy state is split and there appear surface states, which is due to the dangling bonds of atom F of the first layer. Also, it is found that the density of state(DOS) of the top layer F is higher than that of the bulk, which indicates that the surface is active and it is easy to interact with outside. Calculations of Ag adsorption on the MgF2(010) surface show that the 4-fold hollow is energetically favorable and the adsorption is chemical. The analysis on the adsorption mechanism reveals that the electronic transfer mainly occurs between 4p of Ag and 2p and 3s of Mg. The discussion about optical property shows that the absorption in the visual band has a significant increase, which will definitely influence the optical properties of Ag/MgF2 multilayer.

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