Theoretical investigations on the g factors and local structures for Cu2+ in the ZnX (X= O, S and Se) nanocrystals
Theoretical investigations on the g factors and local structures for Cu2+ in the ZnX (X= O, S and Se) nanocrystals
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DOI：
10.1080/00268976.2015.1096425
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发表时间：
2016-01
影响因子：
1.7
通讯作者：
Guo-Liang Li;Shao-yi Wu;B. Teng;Minghe Wu
中科院分区：
文献类型：
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作者：
Guo-Liang Li;Shao-yi Wu;B. Teng;Minghe Wu
摘要采用微扰法计算了ZnX（X = O，S和Se）纳米晶体中Cu 2+的g因子和局域结构，并预测了ZnS：Cu 2+纳米晶体的g因子为各向同性.四个等价的Cu 2 +−X2−键与C4轴之间的键角θ在ZnO、ZnS和ZnSe纳米晶体中分别约为1.26°、1.24°和1.07°，大于理想四面体的键角θ0 <$54.74 °，导致四面体压缩。四角畸变Δθ（= θ − θ0）的下降趋势（ZnO > ZnS > ZnSe）可以归因于由于Cu 2 +−X2−键的减弱，[CuX 4]6−基团的振动相互作用导致动态Jahn-Teller效应的强度降低。各向同性g因子归因于动态Jahn-Teller效应和内应力引起的适当的Δθ。（ZnO < ZnS < ZnSe）g因子的增加可以通过系统的立方场参数Dq、角畸变Δθ和共价因子N的下降来说明。图形摘要
ABSTRACT The g factors and local structures for Cu2+ in the ZnX (X = O, S and Se) nanocrystals at room temperature are theoretically investigated by the perturbation calculations for a tetragonally distorted tetrahedral 3d9 cluster in a consistent way, and the isotropic g factor is predicted for the ZnS:Cu2+ nanocrystals at room temperature. The bond angles θ between the four equivalent Cu2+−X2− bonds and the C4 axis are found to be about 1.26°, 1.24° and 1.07°, respectively, larger in the ZnO, ZnS and ZnSe nanocrystals than that (θ0 ≈ 54.74°) for an ideal tetrahedron, inducing tetragonally compressed tetrahedra. The declining tendency (ZnO > ZnS > ZnSe) of the tetragonal angular distortion Δθ (= θ − θ0) can be ascribed to the decreasing strength of the dynamic Jahn–Teller effect via the vibration interactions of the [CuX4]6− groups due to the weakening Cu2+−X2− bonding. The isotropic g factors are attributable to the appropriate Δθ due to the dynamic Jahn–Teller effect and the internal stress. The slightly increasing (ZnO < ZnS < ZnSe) g factors can be illustrated by the declining cubic field parameter Dq, angular distortion Δθ and covalency factor N of the systems. GRAPHICAL ABSTRACT