Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Nat Commun. 2012;3:1165. doi: 10.1038/ncomms2169.
Entanglement is at the heart of the Einstein-Podolsky-Rosen paradox, where the non-locality is a necessary ingredient. Cooper pairs in superconductors can be split adiabatically, thus forming entangled electrons. Here, we fabricate such an electron splitter by contacting an aluminium superconductor strip at the centre of a suspended InAs nanowire. The nanowire is terminated at both ends with two normal metallic drains. Dividing each half of the nanowire by a gate-induced Coulomb blockaded quantum dot strongly impeds the flow of Cooper pairs due to the large charging energy, while still permitting passage of single electrons. We provide conclusive evidence of extremely high efficiency Cooper pair splitting via observing positive two-particle correlations of the conductance and the shot noise of the split electrons in the two opposite drains of the nanowire. Moreover, the actual charge of the injected quasiparticles is verified by shot noise measurements.
纠缠是爱因斯坦-波多尔斯基-罗森悖论的核心，其中非局域性是必要的组成部分。超导体内的库珀对可以绝热地分裂，从而形成纠缠电子。在这里，我们通过在悬浮的 InAs 纳米线的中心接触铝超导带，制造了这样的电子分裂器。纳米线的两端分别用两个正常金属漏极终止。通过栅极诱导的库仑阻塞量子点将纳米线的每一半分开，由于充电能量很大，极大地阻碍了库珀对的流动，同时仍然允许单个电子通过。我们通过观察导纳的双粒子相关和分裂电子在纳米线的两个相反的漏极中的散粒噪声，提供了极高效率库珀对分裂的确凿证据。此外，通过散粒噪声测量验证了注入准粒子的实际电荷。
