Evolution of the filamentary 3-Kelvin phase in Pb-Ru-Sr2RuO4 Josephson junctions

TL;DR

This paper models how the filamentary 3K superconducting phase at Sr2RuO4-Ru interfaces evolves, revealing how proximity effects influence its topology and impact Josephson junction behavior.

Contribution

It introduces a Ginzburg-Landau model to analyze the topological evolution of the 3K phase in Pb-Ru-Sr2RuO4 junctions, linking topology to experimental Josephson effects.

Findings

Proximity-induced superconductivity in Ru reduces the non-trivial topology onset temperature.

The model reproduces the anomalous temperature dependence of the critical current.

The 3K phase's topology is crucial for Josephson effect behavior.

Abstract

The evolution of the filamentary 3-Kelvin (3K) superconducting phase at the interface between Sr2RuO4 and Ru-metal inclusions is discussed for Pb-Ru-Sr2RuO4 contacts. Using the Ginzburg-Landau model, the influence of proximity-induced superconductivity in Ru on the topology of the 3K phase is analyzed. Because the s-wave order parameter in Ru favors a 3K state of trivial topology, the onset temperature of the phase with a non-trivial topology, which is compatible with the bulk phase of Sr2RuO4, is essentially reduced to the bulk transition temperature. Because the topology of the superconducting state in Sr2RuO4 is crucial for the Josephson effect through Pb-Ru-Sr2RuO4 contacts, this model qualitatively reproduces the experimental observation of the anomalous temperature dependence on the critical current.