Scalable fabrication of graphene nanoribbon quantum dot devices with stable orbital-level spacing
Scalable fabrication of graphene nanoribbon quantum dot devices with stable orbital-level spacing
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DOI：
10.1038/s43246-022-00326-3
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发表时间：
2022-12
影响因子：
7.8
通讯作者：
Toshiaki Kato;Takahito Kitada;Mizuki Seo;W. Okita;Naofumi Sato;M. Shinozaki;Takaya Abe;Takeshi Kumasaka;T. Aizawa;Yui Muto;T. Kaneko;Tomohiro Otsuka
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作者：
Toshiaki Kato;Takahito Kitada;Mizuki Seo;W. Okita;Naofumi Sato;M. Shinozaki;Takaya Abe;Takeshi Kumasaka;T. Aizawa;Yui Muto;T. Kaneko;Tomohiro Otsuka
量子点器件的大规模集成对于实现各种量子器件是必不可少的。石墨烯基量子点由于其低的核自旋密度和弱的自旋轨道相互作用，为自旋量子比特提供了一个很有前途的平台。然而，石墨烯基量子点的集成仍然是一个挑战。在这里，我们展示了使用镍纳米棒技术的石墨烯纳米带基量子点器件的可扩展制造。在纳米带中间形成的精细结构表现出量子点行为，在同一衬底上制造的器件中，超过56%的器件表现出库仑金刚石特征，这表明采用我们的方法可以大规模集成石墨烯纳米带量子点器件。低温测量揭示了基态和激发态之间的轨道能级间距，该间距在~20 K的高温条件下是稳定的。我们解释这种稳定性的纳米带中间形成的非常精细的结构和它们相对较低的有效质量。
Large-scale integration of quantum-dot devices is essential for realizing various quantum devices. Graphene-based quantum dots provide a promising platform for spin qubits because of their low nuclear spin density and weak spin-orbit interaction. However, the integration of graphene-based quantum dots remains a challenge. Here, we demonstrate the scalable fabrication of graphene nanoribbon-based quantum-dot devices using a nickel nanobar technique. Fine structures formed in the middle of the nanoribbons exhibit quantum-dot behavior, and more than 56% of devices fabricated on the same substrate show Coulomb diamond features, indicating that large-scale integration of graphene nanoribbon quantum-dot devices is possible with our method. Cryogenic measurements reveal orbital-level spacings between the ground and excited states that are stable up to high-temperature conditions of ~20 K. We explain this stability in terms of the very fine structures formed in the middle of the nanoribbons and their relatively low effective mass.