Few-Electron Single and Double Quantum Dots in an InAs Two-Dimensional Electron Gas
Few-Electron Single and Double Quantum Dots in an InAs Two-Dimensional Electron Gas
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DOI：
10.1103/prxquantum.2.010321
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发表时间：
2021-02-09
期刊：
影响因子：
9.7
通讯作者：
Ensslin, Klaus
中科院分区：
文献类型：
--
作者：
Mittag, Christopher;Koski, Jonne, V;Ensslin, Klaus
大多数自旋量子比特的原理验证实验都是用基于GaAs基的量子点进行的，因为它们提供了对隧道势垒以及轨道和自旋自由度的出色控制。在这里，我们介绍了在InAs二维电子气中首次实现高质量的单量子点和双量子点，展示了精确的控制，直到少数电子区域，在那里我们观察到明显的近藤效应和单态-三态自旋阻塞。我们测得电子g因子为16，量子点上随机超精细场的典型量级约为0.6mT。我们估计系统中的自旋轨道长度大约为5-10微米(这几乎比InAs纳米结构中通常测量的长度长2个数量级)，这是通过非常对称的量子阱设计实现的。这些良好的性质使InAs二维电子气在地图上成为研究自旋量子比特基本方面的引人注目的宿主。此外，在具有大拉什巴系数的材料中具有弱的自旋-轨道耦合可能为具有自旋-轨道耦合的工程结构开辟了道路，这种耦合可以在空间和/或时间上进行局部控制。
Most proof-of-principle experiments for spin qubits have been performed with GaAs-based quantum dots because of the excellent control they offer over tunneling barriers and the orbital and spin degrees of freedom. Here we present the first realization of high-quality single and double quantum dots hosted in an InAs two-dimensional electron gas, demonstrating accurate control down to the few-electron regime, where we observe a clear Kondo effect and singlet-triplet spin blockade. We measure an electronic g factor of 16 and a typical magnitude of the random hyperfine fields on the quantum dots of approximately 0.6 mT. We estimate the spin-orbit length in the system to be approximately 5 - 10 mu m (which is almost 2 orders of magnitude longer than typically measured in InAs nanostructures), achieved by a very symmetric design of the quantum well. These favorable properties put the InAs two-dimensional electron gas on the map as a compelling host for studying fundamental aspects of spin qubits. Furthermore, having weak spin-orbit coupling in a material with a large Rashba coefficient potentially opens up avenues for engineering structures with spin-orbit coupling that can be controlled locally in space and/or time.