Marín-Suárez Marco, Peltonen Joonas T, Pekola Jukka P
Pico group, QTF Centre of Excellence, Department of Applied Physics, Aalto University, FI-000 76 Aalto, Finland.
Nano Lett. 2020 Jul 8;20(7):5065-5071. doi: 10.1021/acs.nanolett.0c01264. Epub 2020 Jun 18.
Quasiparticle (qp) poisoning is a major issue that impairs the operation of various superconducting devices. Even though these devices are often operated at temperatures well below the critical point where the number density of excitations is expected to be exponentially suppressed, their bare operation and stray microwave radiation excite the non-equilibrium qp's. Here we use voltage-biased superconducting junctions to demonstrate and quantify qp extraction in the turnstile operation of a superconductor-insulator-normal metal-insulator-superconductor single-electron transistor. In this operation regime, excitations are injected into the superconducting leads at a rate proportional to the driving frequency. We reach a reduction of density by an order of magnitude even for the highest injection rate of 2.4 × 10 qp's per second when extraction is turned on.
准粒子（qp）中毒是损害各种超导器件运行的一个主要问题。尽管这些器件通常在远低于临界点的温度下运行，在该温度下激发的数密度预计会被指数抑制，但它们的裸运行和杂散微波辐射会激发非平衡准粒子。在这里，我们使用电压偏置超导结来演示和量化超导体 - 绝缘体 - 正常金属 - 绝缘体 - 超导体单电子晶体管的旋转门操作中的准粒子提取。在这种操作模式下，激发以与驱动频率成正比的速率注入到超导引线中。当开启提取时，即使对于每秒2.4×10个准粒子的最高注入速率，我们也实现了密度降低一个数量级。
