磁场对异质界面上D^-中心的影响

Effect of Magnetic Fields on D^- Center on the Heterointerface

势阱中的类氢杂质的能级问题一直为学术界所长期关注。讨论了异质界面上中性施主D0和负施主离子D-的能量随垂直于界面的磁场的变化情况,同时将磁场和势阱结合起来考虑其对类氢杂质的影响。研究发现随磁场的增大,其对D0基态能的影响越来越大,对其束缚能的影响逐渐变小,而对D-中心,磁场的作用使得D-由非束缚态转变为束缚态。计算中分别选取了两种不同的波函数,分析了这两种波函数的适用范围,利用变分的方法得到此结构中D0中心的基态能量和束缚能与D-中心角动量L=-1自旋三重态的本征能量和束缚能随磁场的变化关系,找到了此三重态由非束缚态转变到束缚态对应磁场的阈值。

The problem of hydrogen-like systems has been extensively studied. Neutral donor and negative donor ion on the heterointerface in magnetic fields are investigated in this paper. The influence of magnetic and potential well has been calculated together. With the increasing of magnetic field, we find that the effect of magnetic fields makes the eigenenergy of D^0 increases more and more. The binding energy increases follo-(wing the) strength of magnetic fields also. But the increasing rate of the binding energy decreases along the growth of fields. For D^(-) center, at zero field, there is only a singlet bound state but no bound triplet state (exists.) The action of the magnetic fields makes the triplet state of D^- change from unbound state to bound state. It is very important for the studying of the energy about hydrogen-like systems like D^- center. We choose two different wave functions for different magnetic fields. Analytic results are obtained for the applicable range of two different wave functions. Using a variational method, we have calculated the ground energies and the binding energies of D^0 center and D^- center for the spin-triplet state of L=-1 in this structure. The optimum of four parameters about the orbit of D^- center and two parameters of D^- center were presented. We found that with the growth of the magnetic fields, the inner and outer orbits are compressed,the inner orbit of D^(-) is alike to the orbit of D^0 .The extend parameters of the outer orbit are similar to the value of cyclotron radius. At zero field, the longitudinal parameter of the outer orbit extend to infinite. According to calculation, we get the corresponding threshold value of the magnetic fields at which the triplet state transforms from unbound state into bound state.