清洁Si(111)表面电子结构的理论研究

本文报道在原子集团模型下用CNDO-SCF方法对清洁Si(111)表面电子结构的系统研究结果:(1)计算了表面上的净电荷分布、电荷转移以及局域在各原子轨道上的电荷;发现T₃⁰,T₃⁺和T₃^-式的表面悬挂键结构较难存在;表面原子趋于形成带有分数电荷的悬挂键,而实际上这些悬挂键彼此结合成弯键;表面原子及其悬挂键上有净电荷积累,且有很强的定域性和取向性。(2)计算了原子集团模型的静关键词：

THEORETICAL STUDY OF THE ELECTRONIC STRUCTURES OF Si(111) SURFACE

The electronic structures of Si (111) surface have been studied by means of molecular orbital theory of SCF-CNDO with the cluster model treatment. The calculated results show that: (1) The distribution and transfer of net charges in thesurface have localized characters at the atomic orbitals. Also, the T₃⁰, T₃⁺ and T₃^-defect forms do not exist easily in practical system. (2) The electronic structures can be discribed with the stoohastic potential, from which one can find out the adsorption site and learn the adsorption dynamic process of ion and ionic molecules adsorbed on the Si (111) surface. (3) The surface states mainly appear in the region from the top of valence band to the centre of gap, and is strongly localized at the atomic orbitals. The above-mentioned results are consistent with some experimental discoveries.