吸附Al,Sn后Si(111)面的电子结构及其比较

COMPARISON BETWEEN THE ELECTRONIC STRUCTURES OF Si(lll) 3^(1/2)×^(1/2)-Sn AND-Al

通过对吸附原子和衬底Si原子由于相互作用而产生的轨道交叠占有几率(OOP)和集团态密度的分析发现吸附Al和吸附Sn的Si(111)面能带中电子的占据状态很不一样,Si(111)3^(1/2)×3^(1/2)-Sn中有一个半充满的表面带,从而使体系具有表面金属性。而Si(111)3^(1/2)×3^(1/2)-Al中电子填满吸附原子和表面Si原子成键的表面态,反键的表面态全空,因此吸Al后的Si(111)面可能出现半导体特性。计算结果与实验结果相符。本文还给出关于Al,Sn和表面Si原子相互作用比较清晰的图象。

By investigating orbital overlap population (OOP) resulting from the interaction between adatom and substrate Si atom, and total density of states of the cluster, it is found that Si(lll) 3^(1/2)×3^(1/2)- Sn has a half filled surface band which makes the surface metallic. But for Si(lll)v 3^(1/2)×3^(1/2)-Al, its bonding surface states are occupied fully with electrons and the antibonding surface states are empty, which makes the surface appear to be semiconducting. These calculation results are consistent with the experimental ones. A clear description on the interactions between Al, Sn and surface Si atom is also presented in this paper.