Si,GaAs(111)表面弛豫效应

本文将赝原子轨道的线性组合方法应用于计算半导体表面电子结构。除了赝势的形状因子以外,不引入任何可调参量。用这方法计算了Si和GaAs(111)理想表面和弛豫表面的电子态和波函数。Si的结果与Appelbaum和Hamann的自洽计算结果在表面能级位置和表面电荷分布两方面都符合得比较好。计算结果表明,当表面Si或Ga原子向内位移时,表面能级向上移动;表面As原子向外位移时,表面能级向下移动。同时,表面态波函数的性质往往也发生较大的变化。关键词：

RELAXATION EFFECTS OF THE (111) SURFACE OF Si AND GaAs

The method of linear combination of pseudoatomic orbitals is applied to calculated the surface electronic structure of semiconductors- Besides the form factors of pseudo-potential, the method does not introduce any adjustable parameters. The electronic states and wave functions of the ideal and relaxed (111) surfaces of Si and GaAs arc calculated. The results of Si is compared with Appelbaum and Hamann's results of self-consistent calculation, it is found that both results are consistent well about the position of surface energy levels and distribution of surface electronic charges. It is shown that the surface energy levels shift upward when the Si or Ga atoms at the surface move inward, and shift downwarol when the As atoms at the surface move outward. At the same time the properties of the wave function of surface states often show more obvious changes.