论文标题
近端量子自旋大厅的异常通量周期性
Anomalous flux periodicity in proximitised quantum spin Hall constrictions
论文作者
论文摘要
我们从理论上分析了二维拓扑绝缘子的螺旋边缘状态之间的长时间限制。收缩横向隧道耦合到两个超导体，并将磁场垂直于二维拓扑绝缘子的平面施加。在没有偏见的情况下（DC和AC Josephson Currents），在隧道耦合的隧道耦合中，在隧道耦合中将约瑟夫森电流计算为二阶。我们表明，在这两种情况下，电流都相对于磁通量获得了异常的$4π$周期性，如果两个边缘彼此之间没有隧道耦合，则不存在。同时提供了设备的表征和边缘之间耦合的可能实验特征的结果是稳定的。负责异常的$4π$周期性的过程是在收缩中，在两个边之间形成库珀对隧道的两个电子之一。
We theoretically analyse a long constriction between the helical edge states of a two-dimensional topological insulator. The constriction is laterally tunnel-coupled to two superconductors and a magnetic field is applied perpendicularly to the plane of the two-dimensional topological insulator. The Josephson current is calculated analytically up to second order in the tunnel coupling both in the absence and in the presence of a bias (DC and AC Josephson currents). We show that in both cases the current acquires an anomalous $4π$-periodicity with respect to the magnetic flux that is absent if the two edges are not tunnel-coupled to each other. The result, that provides at the same time a characterisation of the device and a possible experimental signature of the coupling between the edges, is stable against temperature. The processes responsible for the anomalous $4π$-periodicity are the ones where, within the constriction, one of the two electrons forming a Cooper pair tunnels between the two edges.
