(HgTe)_n(n=2～8)团簇的基态结构和电子性质

Ground-state Structure and Electronic Properties of (HgTe)_n (n=2～8) Clusters

采用密度泛函理论计算,研究了(HgTe)n(n=2～8)团簇基态结构、结合能、能隙、垂直亲和势和二阶能量差分等性质。在广义梯度近似下,对(HgTe)n各种可能的几何结构进行了优化,预测了各团簇的最稳定结构,并对其电子性质进行了计算。研究结果表明:当n=2、n=3时,团簇的最低能量构型是平面结构;当n≥4时,团簇的最低能量结构是三维结构,并且可以看成是由(HgTe)2和(HgTe)3单元组成。(HgTe)n团簇的能隙、垂直亲和势和二阶能量差分表明:(HgTe)3和(HgTe)6是团簇的稳定结构,即n=3和n=6是团簇的幻数。

In this paper,the density functional theory was used to systematically investigate the ground-state structures,binding energy,energy gap,vertical electron affinities and second difference in energy of(HgTe) n(n =2 ～8) clusters.Possible geometrical structures and the relative stability of(HgTe) n(n =2 ～8) clusters were optimized by using the generalized gradient approximation(GGA).The electronic properties were calculated.The results show that the ring-like structures are the ground state structures for n = 2 and 3.While they are three-dimensional structures from n≥4,and they may be considered as being built from(HgTe) 2 and(HgTe) 3 rings.The calculated results on the vertical electron affinities,the second difference in energy and the energy gaps indicate that(HgTe) 3 and(HgTe) 6 are more stable than neighboring clusters.The magic numbers of(HgTe) n are n = 3 and 6.