Ranni Antti, Mannila Elsa T, Eriksson Axel, Golubev Dmitry S, Pekola Jukka P, Maisi Ville F
NanoLund and Solid State Physics, Lund University, Box 118, 22100 Lund, Sweden.
Pico Group, QTF Centre of Excellence, Department of Applied Physics, Aalto University School of Science, P.O. Box 13500, 00076 Aalto, Finland.
Phys Rev Lett. 2022 Nov 11;129(20):207703. doi: 10.1103/PhysRevLett.129.207703.
We measure the rates and coupling coefficients for local Andreev, nonlocal Andreev, and elastic cotunneling processes. The nonlocal Andreev process, giving rise to Cooper pair splitting, exhibits the same coupling coefficient as the elastic cotunneling whereas the local Andreev process is more than 2 orders of magnitude stronger than the corresponding nonlocal one. Theory estimates describe the findings and explain the large difference in the nonlocal and local coupling arising from competition between electron diffusion in the superconductor and tunnel junction transparency.
我们测量了局域安德列夫过程、非局域安德列夫过程和弹性共隧穿过程的速率和耦合系数。产生库珀对分裂的非局域安德列夫过程表现出与弹性共隧穿相同的耦合系数，而局域安德列夫过程比相应的非局域过程强2个数量级以上。理论估计描述了这些发现，并解释了由于超导体中电子扩散与隧道结透明度之间的竞争而导致的非局域和局域耦合的巨大差异。
