Field induced superconducting phase in Superconductor-Normal metal and Superconductor-Superconductor bilayer

TL;DR

This paper investigates how an in-plane magnetic field can induce a superconducting phase in S-N and S-S bilayers by balancing Zeeman effects and energy level splitting, with impurity effects reducing this phase's stability.

Contribution

It reveals the conditions under which a magnetic field can induce superconductivity in bilayers, expanding understanding of proximity effects under magnetic fields.

Findings

Magnetic field induces superconductivity above the paramagnetic limit.

Impurities reduce the stability region of the field-induced superconducting phase.

Balance between Zeeman effect and energy splitting is crucial for phase emergence.

Abstract

We study the proximity effect in a superconductor (S)-normal metal (N) bilayer under in-plane magnetic field. A compensation between the Zeeman effect and the energy splitting between bonding and anti-bonding levels leads to a magnetic field induced superconducting phase in the (H,T) phase diagram of the S-N bilayer well above the standard paramagnetic limit. We demonstrate that the presence of the non-magnetic impurities shrink the region of field induced superconductivity existence in S-N and S-S bilayers.