Spin-polarized proximity effect in superconducting junctions

TL;DR

This paper investigates spin-dependent phenomena in superconducting junctions, revealing how exchange fields and Rashba spin-orbit coupling influence conductance and proximity effects in ballistic and diffusive regimes.

Contribution

It provides new insights into how exchange fields and spin-orbit coupling affect conductance and proximity effects in various superconducting junctions.

Findings

Exchange field suppresses conductance in ballistic junctions.

Rashba spin-orbit coupling can enhance conductance.

Exchange field can enhance the proximity effect in diffusive junctions.

Abstract

We study spin dependent phonomena in superconducting junctions in both ballistic and diffusive regimes. For ballistic junctions we study both ferromagnet / $s$- and d-wave superconductor junctions and two dimensional electron gas / s-wave superconductor junctions with Rashba spin-orbit coupling. It is shown that the exchange field alway suppresses the conductance while the Rashba spin-orbit coupling can enhance it. In the latter part of the article we study the diffusive ferromagnet / insulator / $s$- and d-wave superconductor junctions, where the proximity effect can be enhanced by the exchange field in contrast to common belief. It is shown that the resonant proximity effect originating from the exchange field strongly influences the tunneling conductance and density of states.