SQUIPT - Superconducting Quantum Interference Proximity Transistor

TL;DR

The paper introduces the SQUIPT, a new superconducting interferometer that modulates the density of states in a metallic wire via magnetic flux, achieving high sensitivity with low dissipation, promising improved magnetic field detection.

Contribution

The paper reports the first realization and characterization of the SQUIPT, a novel superconducting quantum interference device with superior sensitivity and minimal dissipation compared to traditional interferometers.

Findings

Flux sensitivities down to ~10^{-5} Φ_0/Hz^{1/2} achieved

Intrinsic dissipation around 100 fW, much lower than conventional devices

Results agree with theoretical predictions, indicating potential for enhanced magnetic sensing

Abstract

We present the realization and characterization of a novel-concept interferometer, the superconducting quantum interference proximity transistor (SQUIPT). Its operation relies on the modulation with the magnetic field of the density of states of a proximized metallic wire embedded in a superconducting ring. Flux sensitivities down to $\sim 10^{-5} \Phi_0$Hz$^{-1/2}$ can be achieved even for a non-optimized design, with an intrinsic dissipation ($\sim 100$ fW) which is several orders of magnitude smaller than in conventional superconducting interferometers. Our results are in agreement with the theoretical prediction of the SQUIPT behavior, and suggest that optimization of the device parameters would lead to a large enhancement of sensitivity for the detection of tiny magnetic fields. The features of this setup and their potential relevance for applications are further discussed.