论文标题
双载架自旋封锁和双层石墨烯双量子点的耦合
Three-carrier spin blockade and coupling in bilayer graphene double quantum dots
论文作者
论文摘要
自由度的自由程度对于理解任何冷凝物质系统至关重要。对旋转机制的了解不仅对于成功控制和操纵自旋量子是必不可少的，而且还发现了研究的设备和材料的基本特性。对于静电定义的双层石墨烯量子点，最近的研究报告了带有强磁场依赖性的自旋 - 延期时间T1的T1，我们研究了电荷构型$（1,2）\ LeftrightArrow（0,3）$。我们检查了自旋阻滞泄漏电流对间点隧道耦合以及外部施加磁场的大小和方向的依赖性。在平面外磁场中，观察到的零视频电流峰可能是由有限温度与铅共同隧道引起的。尽管对于解释观察到的持续锋利的侧峰是必要的，但仍需涉及其他自旋和山谷的混合机制。在平面磁场中，我们观察到零场电流倾角，这归因于自旋Zeeman效应与Kane-Mele自旋相互作用之间的竞争。但是，此电流倾斜的线形状的细节表明，其他潜在机制正在发挥作用。
The spin degree of freedom is crucial for the understanding of any condensed matter system. Knowledge of spin-mixing mechanisms is not only essential for successful control and manipulation of spin-qubits, but also uncovers fundamental properties of investigated devices and material. For electrostatically-defined bilayer graphene quantum dots, in which recent studies report spin-relaxation times T1 up to 50ms with strong magnetic field dependence, we study spin-blockade phenomena at charge configuration $(1,2)\leftrightarrow(0,3)$. We examine the dependence of the spin-blockade leakage current on interdot tunnel coupling and on the magnitude and orientation of externally applied magnetic field. In out-of-plane magnetic field, the observed zero-field current peak could arise from finite-temperature co-tunneling with the leads; though involvement of additional spin- and valley-mixing mechanisms are necessary for explaining the persistent sharp side peaks observed. In in-plane magnetic field, we observe a zero-field current dip, attributed to the competition between the spin Zeeman effect and the Kane-Mele spin-orbit interaction. Details of the line shape of this current dip however, suggest additional underlying mechanisms are at play.
