Banszerus Luca, Möller Samuel, Icking Eike, Watanabe Kenji, Taniguchi Takashi, Volk Christian, Stampfer Christoph
JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany.
Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich, Germany.
Nano Lett. 2020 Mar 11;20(3):2005-2011. doi: 10.1021/acs.nanolett.9b05295. Epub 2020 Feb 27.
We present transport measurements through an electrostatically defined bilayer graphene double quantum dot in the single-electron regime. With the help of a back gate, two split gates, and two finger gates, we are able to control the number of charge carriers on two gate-defined quantum dots independently between zero and five. The high tunability of the device meets requirements to make such a device a suitable building block for spin-qubits. In the single-electron regime, we determine interdot tunnel rates on the order of 2 GHz. Both, the interdot tunnel coupling as well as the capacitive interdot coupling increase with dot occupation, leading to the transition to a single quantum dot. Finite bias magneto-spectroscopy measurements allow to resolve the excited-state spectra of the first electrons in the double quantum dot and are in agreement with spin and valley conserving interdot tunneling processes.
我们展示了在单电子 regime 下通过静电定义的双层石墨烯双量子点进行的输运测量。借助背栅、两个分裂栅和两个指状栅，我们能够在零至五个之间独立控制两个栅定义的量子点上的电荷载流子数量。该器件的高可调性满足了使其成为自旋量子比特合适构建模块的要求。在单电子 regime 下，我们确定了约 2 GHz 量级的点间隧穿速率。点间隧穿耦合以及电容性点间耦合都随量子点占据情况增加，导致向单个量子点的转变。有限偏置磁光谱测量能够分辨双量子点中首个电子的激发态光谱，并且与自旋和谷守恒的点间隧穿过程一致。
