Phase diagram of a current-carrying superconducting film in absence of the magnetic field

TL;DR

This paper maps the phase diagram of current-induced states in superconducting films, revealing how different widths influence the transition from superconducting to resistive states, including vortex and phase-slip phenomena.

Contribution

It provides the first detailed experimental phase diagram of current states in superconducting films, confirming theoretical predictions for vortex and phase-slip transitions.

Findings

Narrow films transition directly from superconducting to resistive state with phase-slip centers.

Intermediate width films exhibit a transition to vortex resistive state at I > 0.8Ic.

Wide films show vortex state within a specific current range, then transition to phase-slip lines.

Abstract

We present the phase diagram for the current states of superconducting films, based on the experimental investigation of the resistive transition induced by transport current. We found that a rather narrow film never enters the vortex state, but experiences direct transition from the purely superconducting state to the resistive state with phase-slip centers as soon as the current exceeds the Ginzburg-Landau critical current Ic. The Meissner current state of the films of intermediate width transforms at I > 0.8Ic to the vortex resistive state which exists within the current interval 0.8Ic < I < Im, where the value Im of the upper critical current is in a good agreement with the theory. The vortex state of wide films is realized within the current region I^{AL} < I < Im, where I^{AL} is the transition point to the vortex state by Aslamazov and Lempitskiy. At I>Im, the wide films enter a vortex-free resistive state with phase-slip lines.