Based on the effective-mass approximation and variational procedure, the ground-state donor binding energy in a cylindrical zinc-blende /GaN symmetric coupled quantum dots (SCQDs) is investigated in the presence of the external electric field. Numerical results show that the donor binding energy increases firstly until a maximum value, and then it begins to drop quickly in all the cases with decreasing the dot radius. As the thickness of left dot and right dot decreases, the donor binding energy increases monotonically at first, reaches a maximum value, and then drops rapidly for an impurity ion located at the right dot center and the middle barrier center. Moreover, the donor binding energy for an impurity ion located at the center of the left dot is insensitive to the variation of dot thickness for large dot thickness due to the Stark effect. Meanwhile, the impurity position plays an important role on the change of the donor binding energy under the external electric field. In particular, the impurity position corresponding to the peak value of the donor binding energy is shifted toward the left QD with increasing the external electric field strength.

中文翻译：

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外部电场对闪锌矿 InxGa1−xN/GaN 对称耦合量子点中浅层施主杂质态的影响

基于有效质量近似和变分过程，在存在外部电场的情况下研究了圆柱形闪锌矿 /GaN 对称耦合量子点 (SCQD) 中的基态供体结合能。数值结果表明，供体结合能先增加，直至达到最大值，然后随着网点半径的减小，在所有情况下都开始迅速下降。随着左点和右点的厚度减小，对于位于右点中心和中间势垒中心的杂质离子，供体结合能首先单调增加，达到最大值，然后迅速下降。此外，由于斯塔克效应，位于左点中心的杂质离子的施主结合能对大点厚度的点厚度变化不敏感。同时，杂质位置对外部电场作用下供体结合能的变化起着重要作用。特别是，随着外部电场强度的增加，对应于供体结合能峰值的杂质位置向左 QD 移动。