Recent studies have shown that the critical currents of several metallic superconducting nanowires and Dayem bridges can be locally tuned using a gate voltage {V_g}. Here, we report a gate-tunable Josephson junction structure constructed from a three-dimensional (3D) niobium nano-bridge junction (NBJ) with a voltage gate on top. Measurements up to 6 K showed that the critical current of this structure can be tuned to zero by increasing {V_g}. The critical gate voltage Vgc was reduced to 16 V and may possibly be reduced further by reducing the thickness of the insulation layer between the gate and the NBJ. Furthermore, the flux modulation generated by Josephson interference of two parallel 3D NBJs can also be tuned using {V_g} in a similar manner. Therefore, we believe that this gate-tunable Josephson junction structure is promising for superconducting circuit fabrication at high integration levels.
@article{arxiv.2308.00953,
title = {Gate-Tunable Critical Current of the Three-Dimensional Niobium Nano-Bridge Josephson Junction},
author = {Shujie Yu and Lei Chen and Yinping Pan and Yue Wang and Denghui Zhang and Guangting Wu and Xinxin Fan and Xiaoyu Liu and Ling Wu and Lu Zhang and Wei Peng and Jie Ren and Zhen Wang},
journal= {arXiv preprint arXiv:2308.00953},
year = {2023}
}