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采用密度泛函理论下广义梯度近似方法,对Mn掺杂Ge基半导体团簇Ge_nMn(n≤8)的结构与磁性进行了理论研究.结果表明:Ge_nMn(n≤8)的最稳定构型与相应的Ge_(n+1)团簇相似.Mn掺杂后团簇的原子平均结合能与纯锗团簇比较近似;能量二次差分表明:Ge_3Mn和Ge_5Mn团簇较相邻团簇表现出较高的稳定性;当n=1,3和6时,HMO-LUMO能隙较大,n=2时,能隙较小,说明GeMn、Ge_3Mn和Ge_6Mn具有相对较好的化学稳定性,而Ge_2Mn具有较高的化学活性.对Ge_nMn(n≤8)团簇的磁性研究发现,除Ge_8Mn的总磁矩为1μB外,其他团簇的总磁矩均为3μB,且团簇的磁性主要来源于Mn原子.
The structure and magnetism of Mn-doped Ge-based semiconductor clusters Ge_nMn (n≤8) have been studied theoretically by means of the generalized gradient approximation of density functional theory. The results show that the most stable structure of Ge_nMn (n≤8) The corresponding Ge_ (n + 1) clusters are similar, the average atomic binding energies of the clusters after Mn doping are similar to those of the pure germanium clusters, and the energy quadratic difference shows that the clusters of Ge_3Mn and Ge_5Mn show better performance than the adjacent clusters High stability. When n = 1, 3, and 6, the energy gap of HMO-LUMO is large. When n = 2, the energy gap is small, indicating that GeMn, Ge_3Mn and Ge_6Mn have relatively good chemical stability, while Ge_2Mn It is found that the magnetic moment of Ge_nMn (n≤8) clusters is 3μB except that the total magnetic moment of Ge_8Mn is 1μB, and the magnetism of clusters mainly comes from Mn atom.