Over the past two decades, investigation of medium-sized silicon clusters has been an active area of research. In order to identify the growth pattern of low-lying clusters from medium to large sized, in this article, we review the structures and relative stability of medium-sized SiN clusters for 21≤N≤50 and N=60. For Si21-Si29, the predicted lowest-energy clusters (except Si27) exhibit prolate structures. For N≥30 the silicon clusters tend to adopt endohedral fullerene configurations. As cluster size increases (N≥41),tetrahedron configurations emerge in the core structures as embryo of bulk diamond lattice. The SiN cluster up to N = 60 has already deviated from the molecule-like behavior of small clusters, but the transition into bulk solid has not completed yet. The structural motif by endohedral fullerene of medium-sized silicon clusters represents an intermediate stage of the transition from molecule-like to bulk-like behavior.%在过去二十年里,对中等尺寸硅团簇的研究一直十分活跃.为阐明低能团簇从中等到大尺寸的生长行为,我们对SiN团簇在21≤N≤50,和N=60的结构和相对稳定性进行论述.对Si21-Si29,除Si27外最低能量结构是扁长形.对N≥30,SlN团簇倾向于形成填充富勒烯结构.随着团簇尺寸的增大(N≥41),內部开始出现四面体结构,可视为金刚石晶格结构形成的初始阶段.当团簇尺寸达到N=60时,其已偏离小团簇的类分子行为,但向块体结构的转变还没完成.中等尺寸硅团簇的填充富勒烯结构可以被看作是从类分子向块体过渡的中间阶段.
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