Department of Applied Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Center for Emergent Matter Science, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
Sci Adv. 2019 Oct 4;5(10):eaaw2194. doi: 10.1126/sciadv.aaw2194. eCollection 2019 Oct.
Cooper pair splitting (CPS) can induce nonlocal correlation between two normal conductors that are coupled to a superconductor. CPS in a double one-dimensional electron gas is an appropriate platform for extracting a large number of entangled electron pairs and is one of the key ingredients for engineering Majorana fermions with no magnetic field. In this study, we investigated CPS by using a Josephson junction of a gate-tunable ballistic InAs double nanowire. The measured switching current into the two nanowires is significantly larger than the sum of the switching current into the respective nanowires, indicating that interwire superconductivity is dominant compared with intrawire superconductivity. From its dependence on the number of propagating channels in the nanowires, the observed CPS is assigned to one-dimensional electron-electron interaction. Our results will pave the way for the utilization of one-dimensional electron-electron interaction to reveal the physics of high-efficiency CPS and to engineer Majorana fermions in double nanowire systems via CPS.
库珀对分裂 (CPS) 可以在与超导体耦合的两个正常导体之间诱导非局域相关性。双一维电子气中的 CPS 是提取大量纠缠电子对的合适平台，也是在没有磁场的情况下工程化马约拉纳费米子的关键组成部分之一。在这项研究中，我们使用门可调弹道 InAs 双纳米线的约瑟夫森结研究了 CPS。测量到的进入两个纳米线的开关电流明显大于进入各个纳米线的开关电流之和，这表明与纳米线内超导相比，线间超导占主导地位。从其对纳米线中传播通道数量的依赖性来看，观察到的 CPS 被分配到一维电子-电子相互作用。我们的结果将为利用一维电子-电子相互作用来揭示高效 CPS 的物理特性以及通过 CPS 在双纳米线系统中工程化马约拉纳费米子铺平道路。
