Electric Field Effects in Mesoscopic Metal Superconductors

The superconducting state of metals is typically thought to be negligibly affected by the presence of externally applied electric fields, given sub-nanometer screening lengths. But recent studies of mesoscopic metallic superconducting channels at millikelvin temperatures observe a reduction of the superconducting critical current under applied gate voltage [1]. We extend these measurements of Ti and Al nanowires and find revealing effects, including voltage tuned oscillations in the critical current as a function of magnetic field. We present possible explanations and experiments underway to evince the origin of the effect.

[1] G. D. Simoni, et al., Nat. Nanotech. 13, 802-805 (2018)