Si在Au(111)面的电子结构和光学性质的第一性原理研究

基于第一性原理,对Si原子在Au(111)表面和体内掺杂的电子结构和光学性质进行了比较研究。结果表明,在Au(111)体内掺杂时,Si原子与周围六个Au原子成键,p电子更局域。电荷密度分析表明,掺杂Si后,Au原子周围的电子密度明显减少,而SiAu原子之间的电子密度明显增加,电子由Au原子向SiAu原子之间转移。通过计算Mul-liken键级表明,SiAu原子之间形成共价键,表面掺杂时的SiAu键级比体内大。吸收谱的计算表明,在体内掺杂Si原子时的吸收谱明显增强。

First-Principles Study on the Electronic Structure and Optical Properties of the Au (111) Surface Doped with a Si Atom

The electronic structure and optical properties of the Au （111） surface doped with a Si atom are studied by using the first-principles calculations. Results show that the Si atom binds with six Au atoms when it is doped in the bulk and the p-orbital electrons are more localized. By analyzing the electron den- sity difference, we find that the electron densities at the Au atoms surrounding the Si atom are relatively smaller, while those between the Au and Si atoms are larger, suggesting the charges transfer from the Au atoms to the Si-Au bonds. The Mulliken bond order shows that the Si atom can form covalent bond with the Au atom, and the surface Si-Au bond order is larger compared with that in bulk. In addition, the calculation of the adsorption spectra shows that the adsorption intensity is obviously enhanced when the Si atom is doped in the bulk.