Electrons in closed systems can exhibit Coulomb blockade (CB) oscillations due to charge quantization. Here, we report CB oscillations in aluminum superconducting islands on InAs nanowires in the open regime. The Al island is connected to the source/drain leads through two contacts: One is fully transmitting while the other is tuned into the tunneling regime. This device configuration is typical for tunneling spectroscopy where charging energy is generally considered negligible. The oscillation periods are 2e or 1e, depending on the gate settings. A magnetic field can induce the 2e to 1e transition. Our result is reminiscent of the "mesoscopic Coulomb blockade" in open quantum dots caused by electron interference.
@article{arxiv.2410.06597,
title = {Coulomb blockade in open superconducting islands on InAs nanowires},
author = {Huading Song and Zhaoyu Wang and Dong Pan and Jiaye Xu and Yuqing Wang and Zhan Cao and Dong E. Liu and Ke He and Runan Shang and Jianhua Zhao and Hao Zhang},
journal= {arXiv preprint arXiv:2410.06597},
year = {2025}
}