BCS supercurrent field-effect transistor

In their original formulation of superconductivity, the London brothers predicted the exponential suppression of an electrostatic field inside a superconductor over the so-called London penetration depth, λ_L. A superconducting body smaller than λ_L is thereby expected to be entirely penetrated and, in principle, affected by electrostatic fields. Yet, the lack of any proof has led to the general belief that superconductors behave like normal metals expelling electrostatic fields over the sub-atomic Thomas-Fermi screening length. Here we report the evidence of electrostatic field penetration leading to full field-effect control of the supercurrent in all-metallic transistors made of a Bardeen-Cooper-Schrieffer superconductor [1]. At low temperature, our titanium field-effect transistors show a monotonic decay of the critical current under increasing electrostatic field up to total quenching for gate voltage values as large as ± 40V. The field effect persists up to ~85% of the critical temperature (~0.41K), and in the presence of sizable magnetic fields. Besides shedding light on a fundamental milestone in physics, our results represent a groundbreaking asset for the realization of an all-metallic superconducting field-effect electronics.

[1] G. De Simoni et al., arXiv:1710.02400v2