Probing interfacial pair breaking in tunnel junctions based on the first and the second harmonics of the Josephson current

TL;DR

This paper demonstrates that analyzing the first and second harmonics of the Josephson current can reveal the presence of significant interfacial pair breaking in tunnel junctions, using Ginzburg-Landau theory.

Contribution

It introduces a method to identify interfacial pair breaking by examining harmonic relations in Josephson junctions, linking theory with measurable quantities.

Findings

Strong interfacial pair breaking leads to j_{2c}j_{dp}>>j_{1c}^2

Standard junctions show the opposite harmonic relation

The approach is based on Ginzburg-Landau theory

Abstract

It will be shown that a pronounced interfacial pair breaking can be identified in Josephson tunnel junctions provided the first j_{1c} and the second j_{2c} harmonics of the supercurrent, as well as the depairing current in the bulk j_{dp}, are known. Namely, within the Ginzburg-Landau theory a strong interfacial pair breaking results in the relation j_{2c}j_{dp}>>j_{1c}^2, while in standard junctions, with negligibly small pair breaking, the relation of opposite character takes place.