硅(111)面表面振动模

本文采用硅(111)面组成的平板结构模型,利用解动力学矩阵的方法,计算了不同层数体系的所有振动模。考虑到晶格弛豫后,该体系才可能存在表面模。由于表面模的激活,解释了Okada关于微晶硅的Raman峰向低波数大幅度移动的现象。同时利用杂化轨道理论计算了由于晶格弛豫引起的表面弹性常数的变化,从而得到表面模的频率为469cm^-1与实验中报道的硅的表面模频率430cm^-1接近。关键词：

SURFACE VIBRATION MODES OF Si(111)

In this paper, the atomic vibration modes of Si(lll) planar strcture with different layers have been calculated using the dynamic matrix method. The Raman frenquency shift, which moves to lower wave number greatly for microcrystals compared with single crystals, can be explained by the activation of surface modes. By hybridized orbical theroy, the change of surface force constants was obtained. The calculated frequency of surface modes, 469cm^-1, is close to the experimental result 430 cm^-1 first reported by Okada.