Anomalous Meissner effect in NS junction with spin-active interface

TL;DR

This paper studies how spin-active interfaces in normal metal/superconductor junctions cause unusual magnetic responses, including oscillations and sign changes in susceptibility, due to odd-frequency pairing effects.

Contribution

It reveals the impact of spin-active interfaces on the Meissner effect, showing oscillatory susceptibility and spontaneous current patterns caused by odd-frequency pairing.

Findings

Susceptibility oscillates with temperature and changes sign.

Magnetic field and current density exhibit spatial oscillations.

Potential spontaneous current pattern formation.

Abstract

We investigate Meissner effect in normal metal/superconductor junctions where the interface is spin-active. We find that orbital magnetic susceptibility of the normal metal shows highly nontrivial behaviors. In particular, the magnetic susceptibility depends on the temperature in an oscillatory fashion, accompanied by its sign change. Correspondingly, magnetic field and current density can spatially oscillate in the normal metal. The possible spontaneous formation of the current pattern is also discussed. These results are attributed to the generation of odd-frequency pairing due to the spin-active interface.