Numerical study of pi-junction using spin filtering barriers

TL;DR

This study numerically explores Josephson transport through ferromagnetic insulators with detailed band structure considerations, revealing conditions for pi junction formation and transitions relevant for quantum device applications.

Contribution

It introduces a numerical approach accounting for band structure in FIs, demonstrating pi junction formation and 0-pi transitions in specific ferromagnetic insulators.

Findings

Pi junction forms in fully spin-polarized FIs like La$_2$BaCuO$_5$

0-pi transition occurs with increasing FI thickness

Strong d-f hybridization in Eu chalcogenides induces pi junction behavior

Abstract

We numerically investigate the Josephson transport through ferromagnetic insulators (FIs) by taking into account its band structure. By use of the recursive Green's function method, we found the formation of the pi junction in the case of the fully spin-polarized FI (FPFI), e.g., La$_2$BaCuO$_5$. Moreover, the 0-pi transition is induced by increasing the thickness of FPFI. On the other hand, Josephson current through the Eu chalcogenides shows the pi junction behavior in the case of the strong d-f hybridization between the conduction d and the localized f electrons of Eu. Such FI-based Josephson junctions may become a element in the architecture of future quantum information devices.