Existence of Shapiro Steps in the Dissipative Regime in Superconducting Weak Links

TL;DR

This paper demonstrates the presence of Shapiro steps in the dissipative regime of superconducting nanobridge weak links, indicating ongoing Josephson coupling and enabling temperature and region size estimations.

Contribution

It provides experimental evidence of Josephson behavior in the dissipative state of superconducting weak links, extending the operational temperature range of related devices.

Findings

Shapiro steps observed in dissipative branch.

Finite Josephson coupling persists in dissipative state.

Effective local temperature can be inferred from Shapiro steps.

Abstract

We present measurements of microwave-induced Shapiro steps in a superconducting nanobridge weak link in the dissipative branch of a hysteretic current-voltage characteristic. We demonstrate that Shapiro steps can be used to infer a reduced critical current and associated effective local temperature. Our observation of Shapiro steps in the dissipative branch hows that a finite Josephson coupling exists in the dissipative state and thus can be used to put an upper limit on the effective temperature and on the size of the region that can be heated above the critical temperature. This work provides evidence that Josephson behaviour can still exist in thermally-hysteretic weak link devices and will allow extension of the temperature ranges that nanobridge based single flux quantum circuits, nanoSQUIDs and Josephson voltage standards can be used.