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论文类型： 期刊论文

发表时间： 2008-01-01

发表刊物： JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE

收录刊物： SCIE、EI

卷号： 5

期号： 1

页面范围： 70-79

ISSN号： 1546-1955

关键字： GaAs; cluster; geometry; electronic property

摘要： The lowest-energy structures and electronic properties of GanAsn clusters up to n = 9 have been investigated using all-electron density functional theory (DFT) within the generalized gradient approximation (GGA). For each cluster size, a number of structural isomers were obtained from an unbiased global search using a genetic algorithm with empirical potential and then further optimized using DFT at the GGA level. For smaller Ga(n)AS(n) clusters with n = 1-5, our calculations successfully reproduce the previously reported lowest-energy structures. Novel cage structures with alternating gallium-arsenic arrangements were observed for n >= 6, and their energies are lower than those of the structures proposed in previous studies. Normal mode analyses have been conducted to confirm that the observed structures are all true minima on the potential energy surface. The size-dependence of cluster properties such as binding energy, ionization potentials, electron affinities, HOMO-LUMO gaps, and Mulliken charge have been computed. Two structural growth patterns have been found for GanAsn clusters, namely growth of fullerene-type cages and growth of structures based on hexagonal prismatic nanorings.