摘要
本文用Si_(39)H_(32)、Si_(35)H_(30)、Si_(91)H_(64)和Si_(58)H_(46)原子集团模型模拟Si(112)高密勒指数面,探讨了模拟Si(112)表面模型的选取,计算了诸原子集团中的电荷分布。发现,Si(112)表面元胞所处的环境对表面元胞中电荷分布性质有根本影响,大规模原子集团模型Si_(91)H_(64)较好地模拟了Si(112)表面的性质。不同的模型下都得到一个共同的电子结构特性,即表面原子在悬键方向存在电荷的趋向集居,且这种性质对台面原子尤为明显。这个结果说明,表面电荷的趋向集居是由表面原子的结构特点决定的。
Large cluster models of Si_(39)H_(32),Si_(35)H_(30),Si_(91),H_(64)and Si_(58)H_(46)are used to simulate the Si(112)surface, respectively. The net charge and its distribution of these systems are calculated bymeans of semiempirical CNDO-SCF method. The results indicate that the cluster modelsSi_(39)H_(32)and Si_(35)H_(30)are not large enough to simulate the Si (112) surface, and the cluster ofSi_(91)H_(64)is a reasonable one for modeling Si(112) sur(?)ace. We also found that the net chargesexisting at surface atoms were concentrated in the cirection (or in the opposite direction)ofthe corresponding dangling bonds-this property is determined by the atomic structure ofthe surface.
基金
国家自然科学基金
