采用密度泛函理论研究了InnAsn (n≤90)管状团簇以及单壁InAs纳米管的几何结构、稳定性和电子性质.小团簇InAsn(n=1-3)基态结构和电子性质的计算结果与已有报道相一致.当n≧4时优化得到了一族稳定的管状团簇,其结构基元(In原子与As原子交替排列的四元环和六元环结构)满足共同的衍化通式.团簇的平均结合能表明横截面为八个原子的管状团簇稳定性最好.管状团簇前线轨道随尺寸的变化规律有效地解释了一维稳定管状团簇的生长原因,同时也说明了实验上之所以能合成InAs纳米管的微观机理.此外,研究结果表明通过管状团簇的有效组装可得到宽带隙的InAs半导体单壁纳米管.%The geometric structures,stabilities,and electronic properties of InnAsn tubelike clusters at up to n=90 and single-walled InAs nanotubes (InAsNTs) were studied by density functional theory (DFT)calculations.The lowest-energy structures and electronic properties of the small InnAsn (n=1-3) clusters are consistent with those found in earlier studies.A family of stable tubelike structures with In-As alternating arrangement was observed when n≧4 and their structural units (four-membered rings and sixmembered rings) obey the general developing formula.The average binding energies of the clusters show that the tubelike cluster with eight atoms in the cross section is the most stable cluster.The sizedependent properties of the frontier molecular orbital surfaces explain why we can successfully obtain long and stable tubelike clusters.They also illustrate the reason why InAsNTs can be synthesized experimentally.We also found that the single-walled InAsNTs can be prepared by the proper assembly of tubelike clusters to form semiconductors with large bandgap.
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