Wang Xumin, Huang Shaoyun, Wang Ji-Yin, Pan Dong, Zhao Jianhua, Xu H Q
Beijing Key laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and Department of Electronics, Peking University, Beijing 100871, China.
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
Nanoscale. 2021 Jan 21;13(2):1048-1054. doi: 10.1039/d0nr07115c.
A single quantum dot serving as a charge sensor is integrated to scalable double quantum dots using local top finger-gate techniques on two neighboring pure-phase InAs nanowires. The single dot built on one nanowire capacitively couples one of the double dots constructed on another nanowire via a metal bridge gate. The charge occupation states of double quantum dots can be accurately monitored by the sensor even in a few-electron regime in which transport tunneling current through the double dots vanishes. In the tunneling spectroscopy of double dots, electron inter dot tunneling process is absent; however, it can be illustrated by the sensor in terms of a transconductance line between the two closest triple points. Thus, tunnel coupling strength between the double dots is quantitatively extracted from the detectable charge transition. The highly tunable multiple quantum dots with integrated charge sensors on InAs nanowires could be an essential building block for quantum information processing technology.
利用局部顶指栅技术，在两根相邻的纯相砷化铟纳米线上，将作为电荷传感器的单个量子点集成到可扩展的双量子点中。构建在一根纳米线上的单个量子点通过金属桥接栅与构建在另一根纳米线上的双量子点之一电容耦合。即使在双量子点的传输隧穿电流消失的少电子体系中，传感器也能精确监测双量子点的电荷占据状态。在双量子点的隧穿光谱中，不存在电子点间隧穿过程；然而，传感器可以根据两个最接近的三重点之间的跨导线来进行说明。因此，可从可检测的电荷跃迁中定量提取双量子点之间的隧穿耦合强度。在砷化铟纳米线上集成电荷传感器的高度可调谐多量子点可能是量子信息处理技术的重要组成部分。
