Electric instability in superconductor-normal conductor ring

TL;DR

This paper explores the non-linear electrodynamics of a superconductor-normal conductor ring, revealing complex current-voltage behavior, high magnetic flux sensitivity, and spontaneous oscillations with high frequencies in Andreev interferometers.

Contribution

It introduces a detailed analysis of non-linear effects, including oscillations and flux sensitivity, in a superconductor-normal conductor ring, advancing understanding of its electrodynamics.

Findings

Current-voltage characteristic exhibits multiple intersecting loops.

Transport current sensitivity to magnetic flux is comparable to SQUIDs.

Spontaneous non-linear oscillations can reach frequencies up to 10^{12} Hz.

Abstract

Non-linear electrodynamics of a ring-shaped Andreev interferometer (superconductor-normal conductor-superconductor hybrid structure) inductively coupled to a circuit of the dissipative current is investigated. The current-voltage characteristics (CVC) is demonstrated to be a series of loops with several branches intersecting in the CVC origin. The sensitivity of the transport current to a change of the applied external magnetic flux can be comparable to the one of the conventional SQUID's. Spontaneous arising of coupled non-linear oscillations of the transport current, the Josephson current and the magnetic flux in Andreev interferometers are also predicted and investigated. The frequency of these oscillations can be varied in a wide range, while the maximal frequency can reach $\omega_{max} \sim 10^{12}$ $sec^{-1}$.