High-energy electron injection in top-gated niobium microbridges for enhanced power efficiency and localized control

Abstract

This study explores gate-controlled superconductivity in metallic superconductors by employing a top-gate architecture with a 15 nm monocrystalline h-BN as a gate dielectric. The transport properties under gate voltage can be elucidated by injecting high-energy electrons, following the Fowler–Nordheim electron field emission model. In contrast to conventional resistive Joule heating, high-energy electron injection with top-gating exhibits excellent power efficiency in suppressing superconductivity. A nearby superconducting bridge, which serves as a thermometer, indicates that our top-gate device can achieve good local control, well limited within a distance of 0.6 μm due to the very low top-gating power. These findings are essential for advancing efficient and highly integrated tunable superconducting electronic devices.