GaAs(110)面的电子结构

本文研究GaAs(110)面旋转弛豫的电子结构,采用一个原子集团来模拟GaAs(110)面,在其内边界上用一些“类Ga”和“类As”原子来钝化伸向体内的悬挂键,以消除由于有限模型而引起的多余边界效应。用EHT方法计算集团的总能量,由能量极小定出GaAs(110)面最稳定的弛豫位置为表面旋转角ω=18°,表面Ga原子向体内下降0.33?,As原子上升0.13?,这与Pandey等人从光电子部分产额谱所得的结果基本一致。本文还计算了理想和弛豫的GaAs(110)面的态密度,发现对于理想的(110)面禁带中确实存在一个空的表面峰。弛豫后,该峰向上移动进入导带,禁带中不再出现表面峰,与实验结果相符。 关键词：

THE SURFACE STRUCTURE OF GaAs(110)

The rotational relaxation of the GaAs (110) surface is considered. A cluster model is used for simulating the crystal surface, and some quasi atoms are added in order to saturate the dangling bonds in the cluster boundary. The stable relaxation geometry of the GaAs (110) surface is determined by minimizing the total energy of the cluster calculated by the Extended Huckel Method. According to the calculation a value of 18° for the tilted angle of the surface bond is suggested, it is in fairly good agreement with that given by the partial yield photoelectron spectroscopy. The density of states for the cluster is also calculated, it is shown that for this relaxation model there is no empty cation state existing within the band gap.