Charge detection of a quantum dot under different tunneling barrier symmetries and bias voltages.
Charge detection of a quantum dot under different tunneling barrier symmetries and bias voltages.
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DOI：
10.1039/d2nr03459j
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发表时间：
2021-05
期刊：
影响因子：
6.7
通讯作者：
Weijie Li;Jingwei Mu;Zhi-Hai Liu;Shaoyun Huang;D. Pan;Yuanjie Chen;Ji-Yin Wang;Jianhua Zhao;H. Xu
中科院分区：
文献类型：
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作者：
Weijie Li;Jingwei Mu;Zhi-Hai Liu;Shaoyun Huang;D. Pan;Yuanjie Chen;Ji-Yin Wang;Jianhua Zhao;H. Xu
我们报道了一个耦合量子点（QD）系统的实现，该系统包含两个单量子点，由两个相邻的InAs纳米线制成。其中一个量子点（传感器量子点）作为电荷传感器来检测另一个量子点（目标量子点）中的电荷状态转变。我们研究了目标量子点的隧穿势垒不对称性对目标量子点中电荷态跃迁探测可见性的影响。通过电子通过目标量子点传递的直接信号和传感器量子点显示的目标量子点中电荷态跃迁的检测信号，同时测量了不同势垒栅电压配置下目标量子点的电荷稳定性图。我们发现，只有当目标量子点的隧穿势垒接近对称时，传感器量子点的跨导信号才能观察到目标量子点的完整库仑钻石边界和涉及目标量子点激发态的输运过程。通过分析两个隧穿速率之比对电子通过目标量子点传递过程的影响，可以解释这些观察结果。我们的结果表明，在构建电荷传感器集成量子点器件时，考虑隧道耦合的对称性是很重要的。
We report the realization of a coupled quantum dot (QD) system containing two single QDs made in two adjacent InAs nanowires. One QD (sensor QD) was used as a charge sensor to detect the charge state transitions in the other QD (target QD). We investigated the effect of the tunneling barrier asymmetry of the target QD on the detection visibility of the charge state transitions in the target QD. The charge stability diagrams of the target QD under different configurations of barrier-gate voltages were simultaneously measured via the direct signals of electron transport through the target QD and via the detection signals of the charge state transitions in the target QD revealed by the sensor QD. We find that the complete Coulomb diamond boundaries of the target QD and the transport processes involving the excited states in the target QD can be observed in the transconductance signals of the sensor QD only when the tunneling barriers of the target QD are nearly symmetric. These observations were explained by analyzing the effect of the ratio of the two tunneling rates on the electron transport processes through the target QD. Our results imply that it is important to consider the symmetry of the tunnel couplings when constructing a charge sensor integrated QD device.