Real-time detection of electron tunnelling in a quantum dot
Real-time detection of electron tunnelling in a quantum dot
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DOI：
10.1038/nature01642
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发表时间：
2003-05-22
期刊：
影响因子：
64.8
通讯作者：
Rimberg, AJ
中科院分区：
文献类型：
--
作者：
Lu, W;Ji, ZQ;Rimberg, AJ
电子之间存在强（库仑）相互作用的纳米结构被预测表现出时间电子相关性（1）。虽然有充分的实验证据表明存在这种相关性（2），但工程纳米结构中的电子动力学仅在长时间尺度上直接观察到（3）。与电流或电荷波动（4）相关的更快的动态通常从直流（或准直流）电流测量中推断出来。最近，人们对电子动力学的兴趣有所上升，部分原因是人们认识到，关于电子相互作用的额外信息可以在直流电的散粒噪声（5）或更高的统计矩（6，7）中找到。此外，对量子计算的兴趣刺激了对量子比特（qubit）读出技术的研究（8，9），对于许多凝聚态系统，这最终归结为单个电子电荷的单次测量。在这里，我们报告了使用集成射频单电子晶体管（10，11）在量子点中实时观察单个电子隧穿事件。我们用电子计数法直接测量量子点的隧穿率和电荷态的占据几率。我们的研究结果提供了证据，有利于长（10亩或以上）非弹性散射时间在几乎孤立的点。
Nanostructures in which strong (Coulomb) interactions exist between electrons are predicted to exhibit temporal electronic correlations(1). Although there is ample experimental evidence that such correlations exist(2), electron dynamics in engineered nanostructures have been observed directly only on long timescales(3). The faster dynamics associated with electrical currents or charge fluctuations(4) are usually inferred from direct (or quasi-direct) current measurements. Recently, interest in electron dynamics has risen, in part owing to the realization that additional information about electronic interactions can be found in the shot noise(5) or higher statistical moments(6,7) of a direct current. Furthermore, interest in quantum computation has stimulated investigation of quantum bit (qubit) readout techniques(8,9), which for many condensed-matter systems ultimately reduce to single-shot measurements of individual electronic charges. Here we report real-time observation of individual electron tunnelling events in a quantum dot using an integrated radio-frequency single-electron transistor(10,11). We use electron counting to measure directly the quantum dot's tunnelling rate and the occupational probabilities of its charge state. Our results provide evidence in favour of long (10 mus or more) inelastic scattering times in nearly isolated dots.