Condition of the occurrence of phase slip centers in superconducting nanowires under applied current or voltage

TL;DR

This paper investigates the conditions under which phase slip centers occur in superconducting nanowires, highlighting the role of relaxation times and providing a simple model based on experimental data.

Contribution

It introduces a simple model predicting phase slip center formation in superconducting nanowires based on relaxation time competition, supported by experimental results.

Findings

Phase slip centers depend on the competition between relaxation times.

Periodic oscillations occur if phase relaxation is faster than order parameter relaxation.

The model explains conditions for phase slip phenomena in superconducting nanowires.

Abstract

Experimental results on the phase slip process in superconducting lead nanowires are presented under two different experimental conditions: constant applied current or constant voltage. Based on these experiments we established a simple model which gives us the condition of the appearance of phase slip centers in a quasi-one-dimensional wire. It turns out that the competition between two relaxations times (relaxation time of the absolute value of the order parameter $\tau_{|\psi|}$ and relaxation time of the phase of the order parameter in the phase slip center $\tau_{\phi}$) governs the phase slip process. Phase slip phenomena, as periodic oscillations in time of the order parameter, is possible only if the gradient of the phase grows faster than the value of the order parameter in the phase slip center, or equivalently if $\tau_{\phi}<\tau_{|\psi|}$.