A 2 x 2 quantum dot array with controllable inter-dot tunnel couplings
A 2 x 2 quantum dot array with controllable inter-dot tunnel couplings
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DOI：
10.1063/1.5025928
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发表时间：
2018-04-30
影响因子：
4
通讯作者：
Vandersypen, Lieven M. K.
中科院分区：
文献类型：
--
作者：
Mukhopadhyay, Uditendu;Dehollain, Juan Pablo;Vandersypen, Lieven M. K.
静电定义的量子点阵列中电子之间的相互作用自然可以通过费米-哈伯德哈密顿量来描述。此外，这些系统的高度可调性使它们成为模拟哈伯德模型不同状态的强大平台。然而，大多数量子点阵列的实现仅限于一维线性阵列。在这封信中，我们提出了一种使用双层栅极技术在 AlGaAs/GaAs 异质结构中静电定义的 2 x 2 量子点方形晶胞。我们使用附近的量子点作为电荷传感器来探测阵列的特性。我们表明，我们可以确定性地、动态地控制单电子到少电子区域中每个量子点的电荷占据。此外，我们还实现了 0-40 mu eV 范围内最近邻隧道耦合的同步单独控制。最后，我们演示了通过泡利自旋封锁通过自旋到电荷的转换来快速（类似于 1 μs）单次读出点中电子的自旋状态。这些进步为二维模拟量子模拟铺平了道路，这是以前在量子点系统中无法实现的。 (C) 2018 年作者。
The interaction between electrons in arrays of electrostatically defined quantum dots is naturally described by a Fermi-Hubbard Hamiltonian. Moreover, the high degree of tunability of these systems makes them a powerful platform to simulate different regimes of the Hubbard model. However, most quantum dot array implementations have been limited to one-dimensional linear arrays. In this letter, we present a square lattice unit cell of 2 x 2 quantum dots defined electrostatically in an AlGaAs/GaAs heterostructure using a double-layer gate technique. We probe the properties of the array using nearby quantum dots operated as charge sensors. We show that we can deterministically and dynamically control the charge occupation in each quantum dot in the single- to few-electron regime. Additionally, we achieve simultaneous individual control of the nearest-neighbor tunnel couplings over a range of 0-40 mu eV. Finally, we demonstrate fast (similar to 1 mu s) single-shot readout of the spin state of electrons in the dots through spin-to-charge conversion via Pauli spin blockade. These advances pave the way for analog quantum simulations in two dimensions, not previously accessible in quantum dot systems. (C) 2018 Author(s).