Si(111)3^(1/2)×3^(1/2)R30°-Ag表面结构的运动学低能电子衍射及数据平均方法的研究

Atomic Structure of Si(111) 3^(1/2)×3^(1/2)R30°-Ag Surface

本文用运动学低能电子衍射(KLEED)及数据平均方法(CMTA)对Si(111)3^(1/2)× 3^(1/2)R30°-Ag表面结构进行了研究,经过彻底的优化,我们得到了和实验最相符合的模型。该表面最上层由Ag原子组成,它们排成“链式的蜂窝状三聚体”(honeycomb-chained-trimer)结构,在它们以下0.79A处是每个表面原胞中有三个Si原子的Si层,接下来的是形变很大的体状的Si双层。我们的分析还表明该表面存在深弛豫,这是该表面一个尚未被报道的重要特征。

The atomic structure of the Si(111)3^(1/2)×3^(1/2)R30°-Ag surface is investigated usingthe improved kinematic low-energy electron diffraction approach in conjunction with the constant-momentum transfer averaging technique (KLEED/CMTA). The topmost layer of the surfaceis formed by Ag atoms with a honeycomb-chained-triangle arrangement.Below the Aglayer, there exists a Si trimer layer followed by bulklike Si double layers. The3^(1/2)-reconstructionextends down to the fifth Si layer, and there is an oscillatory multilayer relaxation in theselvage region, which had never been reported before. We give all the structural parametersof the model.