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硅锗团簇结构与电子性质的研究对于研发新型微电子材料具有重要意义.将遗传算法和基于密度泛函理论的紧束缚方法相结合,研究了SimGen(m+n=9)团簇的原子堆积结构和电子性质.计算结果发现,SimGen(m+n=9)团簇存在两种低能原子堆积稳定构型:带小金字塔的五边形双锥堆积和带桥位Ge原子的四面体紧密堆积.随着团簇内锗原子数目的逐渐增加,两种堆积结构均出现明显的转变,其中最低能量的几何结构由单侧带相邻双金字塔的五边形双锥结构转变为双侧带相邻单金字塔的五边形双锥结构.随着原子堆积结构的变化,团簇内原子电荷分布及电子最高占据轨道与电子最低未占据轨道的能隙随团簇内所含硅和锗元素组分的不同呈现出明显的差异.
The study on the structure and electronic properties of SiGe clusters is very important for the research and development of new microelectronic materials.Based on the genetic algorithm and the tight binding method based on density functional theory, the atomic structure of SimGen (m + n = 9) clusters The results show that there are two kinds of low-energy atomic stacking stable structures in SimGen (m + n = 9) cluster: pentagonal bipyramid stacking with small pyramids and tetrahedral compact with bridging Ge atoms Accumulation.With the gradual increase of the number of germanium atoms in the cluster, the two kinds of stacking structure all show obvious changes, in which the lowest energy geometric structure is changed from the pentagonal bipyramidal structure with the adjacent double pyramids to the bilateral bands Pentagonal bipyramid structure of adjacent single pyramids.With the change of atomic packing structure, the atomic charge distribution in the clusters and the energy gap of the lowest occupied orbital of electrons and the lowest unoccupied orbital of the electron vary with the content of silicon and germanium contained in the clusters Differences in components show significant differences.