Geometric pi Josephson junction in d-wave superconducting thin films

TL;DR

This paper proposes a new design for a pi Josephson junction using a d-wave superconductor with specific boundary geometry, demonstrating the transition to pi state at low temperatures and small sizes through microscopic calculations.

Contribution

It introduces a novel geometric approach to realize pi Josephson junctions in d-wave superconductors, supported by self-consistent microscopic theory calculations.

Findings

Transition to pi junction at low temperatures

Transition occurs for small geometries

Critical current behavior confirmed by theory

Abstract

A novel way to realize a pi Josephson junction is proposed, based on a weak link in an unconventional d-wave superconductor with appropriately chosen boundary geometry. The critical current of such a junction is calculated from a fully selfconsistent solution of microscopic Eilenberger theory of superconductivity. The results clearly show, that a transition to a pi Josephson junction occurs for both low temperatures and small sizes of the geometry.