Effect of double quantum dot asymmetry on electron localization
Effect of double quantum dot asymmetry on electron localization
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DOI：
10.1142/s0217984923420058
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发表时间：
2023-11-30
影响因子：
1.9
通讯作者：
Vlahovic，Branislav
中科院分区：
文献类型：
--
作者：
Filikhin，Igor;Karoui，Abdennaceur;Vlahovic，Branislav
本文研究了由一对量子点组成的二元量子系统中电子的局域化问题。传统的双量子点系统的理论考虑仅限于这种双量子点(DQd)中的量子点在各方面都相同的对称情况。在这篇文章中，我们通过将二维(2D)DQD作为双量子阱(DQW)来研究DQD中打破量子点相似性的效应。这是通过求解薛定谔方程来实现的，所选参数用于描述InAs/GaAs异质结。我们计算了电子受限的能谱和局域/非局域空间态的谱分布。同时考虑了对称和非对称量子波形状，并比较了它们的效果。在二能级系统理论的框架内解释了对称性破缺的影响。我们描述了DQW中的量子波弱耦合和强耦合情况。特别地，我们证明了在弱量子波耦合的情况下，理想DQW的相干性是不稳定的。在所提出的方法框架内，讨论了在DQd上实现的电荷量子比特，并作为例子，提出了基于几乎理想DQd的量子比特。
In this paper, we study the localization of an electron in a binary quantum system formed by a pair of quantum dots (QDs). The traditional theoretical consideration of such systems is limited to the symmetrical case when QDs in such double quantum dot (DQD) are assumed identical in all respects. In this paper, we model the effects of breaking QD similarities in a DQD by studying two-dimensional (2D) DQDs as a double quantum well (DQW). This is done by solving the Schrödinger equation, with parameters chosen to describe an InAs/GaAs heterostructure. We calculate the energy spectrum of the electron confinement and the spectral distribution of localized/delocalized spatial states. Both symmetric and asymmetric QW shapes are considered and their effects are compared. The effects of symmetry breaking are explained within the framework of the two-level system theory. We delineate the QW weak and strong coupling cases in DQW. In particular, we show that the coherence in ideal DQW is unstable in the case of a weak QW coupling. Within the framework of the proposed approach, a charge qubit realized on a DQD is discussed and, as an example, a qubit based on an almost ideal DQD is proposed.