Phase slips dynamics in gated Ti and V all-metallic supercurrent nano-transistors: a review

Abstract

The effect of electrostatic gating on metallic elemental superconductors was recently demonstrated in terms of modulation of the switching current and control of the current phase relation in superconducting quantum interferometers. The latter suggests the existence of a direct connection between the macroscopic quantum phase (φ) in a superconductor and the applied gate voltage. The measurement of the switching current cumulative probability distributions (SCCPD) is a convenient and powerful tool to analyze such relation. In particular, the comparison between the conventional Kurkijärvi-Fulton-Dunkleberger model and the gate-driven distributions give useful insights into the microscopic origin of the gating effect. In this review, we summarize the main results obtained in the analysis of the phase slip events in elemental gated superconducting weak-links in a wide range of temperatures between 20 mK and 3.5 K. Such a large temperature range demonstrates both that the gating effect is robust as the temperature increases, and that fluctuations induced by the electric field are not negligible in a wide temperature range.

Gate-control of the current-flux relation of a Josephson quantum interferometer based on proximitized metallic nanojuntions

“…This picture does not rely on novel physics. Yet, it does not seem compatible with some of the observed phenomenology such as the absence of a sum rule between currents originating from different gates 4 , the response of in-vacuum suspended gated superconducting nanowires 21 , and the non-thermal character of the switching current probability distributions of GSTs 22,23 . A possible alternative [24][25][26] explanation relies on the analogy between the creation of an electron-positron couple from the vacuum by a constant electric field in quantum electrodynamics (i.e., the so-called Sauter-Schwinger effect), and the creation of an excited condensate in a BCS superconductor.…”

Gate Control of the Current–Flux Relation of a Josephson Quantum Interferometer Based on Proximitized Metallic Nanojuntions

“…Yet, it does not seem compatible with some of the observed phenomenology such as the absence of a sum rule between currents originating from different gates, 4 the response of in-vacuum suspended gated superconducting nanowires, 21 and the nonthermal character of the switching current probability distributions of GSTs. 22,23 A possible alternative 24−26 explanation relies on the analogy between the creation of an electron−positron couple from the vacuum by a constant electric field in quantum electrodynamics (i.e., the socalled Sauter−Schwinger effect) and the creation of an excited condensate in a BCS superconductor. As another choice, the involvement of a voltage-driven orbital polarization at the surface of the superconductor has been proposed 27−29 to be responsible for an unconventional phase reconstruction of the superconducting order parameter, leading to weakening and destruction of superconductivity.…”