Aumentado J, Keller Mark W, Martinis John M, Devoret M H
National Institute of Standards and Technology, Boulder, Colorado 80305-3337, USA.
Phys Rev Lett. 2004 Feb 13;92(6):066802. doi: 10.1103/PhysRevLett.92.066802.
We have fabricated single-Cooper-pair transistors in which the spatial profile of the superconducting gap energy was controlled by oxygen doping. The profile dramatically affects the switching current vs gate voltage curve of the transistor, changing its period from 1e to 2e. A model based on nonequilibrium quasiparticles in the leads explains our results, including the observation that even devices with a clean 2e period are "poisoned" by small numbers of these quasiparticles.
我们制造了单库珀对晶体管，其中超导能隙能量的空间分布通过氧掺杂来控制。这种分布显著影响晶体管的开关电流与栅极电压曲线，使其周期从1e变为2e。基于引线中非平衡准粒子的模型解释了我们的结果，包括观察到即使具有清晰2e周期的器件也会被少量这些准粒子“毒害”。
