Dynamics of Gate-Controlled Superconducting Dayem Bridges

TL;DR

This study investigates the dynamic behavior of gate-controlled superconducting Dayem bridges integrated into resonators, revealing differences in response times based on gate configuration, which informs their potential use in superconducting electronics.

Contribution

The paper provides the first time-domain analysis of gate-controlled supercurrent in Dayem bridges, comparing side-coupled and remote injector configurations.

Findings

Significant impedance changes at ~1 V gate voltage

Remote injector yields faster, more controlled response

Differences in time-domain dynamics between configurations

Abstract

Local control of superconducting circuits by high-impedance electrical gates offers potential advantages in superconducting logic, quantum processing units, and cryoelectronics. Recent experiments have reported gate-controlled supercurrent in Dayem bridges made of metallic superconductors, mediated by direct current leakage, out-of-equilibrium phonons, or possibly other mechanisms. However, a time-domain characterization of this effect has been lacking. Here, we integrate Dayem bridges made of Niobium on Silicon into coplanar-waveguide resonators, and measure the effect of the gate voltage at steady state and during pulsed operation. We consider two types of arrangements for the gate: a side-coupled gate and a remote injector. In both cases, we observe sizable changes in the real and the imaginary part of the constriction's impedance for gate voltages of the order of 1 V. However, we find striking differences in the time-domain dynamics, with the remote injector providing a faster and more controlled response. Our results contribute to our understanding of gate-controlled superconducting devices and their suitability for applications.