High-energy electron local injection in top-gated metallic superconductor switch

作者：Hongmei Du, Zuyu Xu, Zihan Wei, Dingding Li, Shixian Chen, Wanghao Tian, Ping Zhang, Yang-Yang Lyu, H. S. Sun, Yong-Lei Wang, Huabing Wang, Peiheng Wu · 发表于：Superconductor Science and Technology · 年份：2023 · DOI：10.1088/1361-6668/ace65f · 被引用次数：9 · 研究领域：Physics of Superconductivity and Magnetism、Quantum and electron transport phenomena、Superconductivity in MgB2 and Alloys

Abstract The gate-tunable superconductivity in metallic superconductors has recently attracted significant attention due to its rich physics and potential applications in next-generation superconducting electronics. Although the operating principles of these devices have been attributed to the small leakage currents of high-energy electrons in recent experiments, the generated phonons can spread over considerable distances in the substrate, which may limit their further applications. Here, we utilize a top gate structure with monocrystalline h-BN as a gate dielectric and demonstrate the gate-adjustable supercurrent in a metallic Nb microbridge. The gate current of the devices perfectly follows the Fowler–Nordheim law of field emission, indicating that the injection of high-energy electrons presumably causes the suppression of the supercurrent. Our devices reduce the distance between the gate and the microbridge to a few nanometers or less, significantly minimizing the generated phonons’ spreading distance and power dissipation in the substrate or surrounding environment. These observations demonstrate that top-gated metallic superconducting switches with local electron injection can improve the device integration density, providing us with more versatile and practical opportunities to explore superconducting circuit architecture.