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分别采用单带重空穴近似和六带Kronig-Penney模型,对垂直耦合锗量子点在不同耦合距离下的空穴态特性进行了计算,并探讨了自旋-轨道的相互作用对空穴态对称性的影响.计算结果表明:多带耦合的框架下,随着量子点垂直间距的增大,空穴基态从成键态转变为反键态,而且价带基态能级和第一激发态能级发生反交叉现象,这与单带模型下得到的相应结果存在较大差异.通过分析六带模型计算得到的成、反键态波函数,轻、重空穴态和自旋-轨道分裂态对特征空穴态波函数的贡献比例随着量子点垂直间距的增大发生了转变,并最终导致量子点空穴基态波函数由成键态转变为反键态.
The hole-state properties of vertically-coupled germanium quantum dots at different coupling distances were calculated using the single-band heavy-hole approximation and the six-band Kronig-Penney model, respectively. The effects of spin-orbit interactions on the hole states The results show that under the framework of multi-band coupling, the ground state of the hole changes from the bonding state to the antibonding state with the increase of the vertical spacing of the quantum dots, and the valence band ground state level and the first excited state Which is different from the corresponding results obtained in the single-band model.By analyzing the wave functions of the as-formed and the anti-bond states calculated by the six-band model, the states of light and heavy cavities and spin-orbit splitting The contribution ratio of the state to the characteristic cavity state wave function changes with the increase of the vertical spacing of the quantum dots, and eventually leads to the change of the ground state wave function of the quantum dot cavity from the bonding state to the antibonding state.