Magnetic Field Effect in Josephson tunneling between d-Wave Superconductors

TL;DR

This paper investigates how magnetic fields influence Josephson tunneling between d-wave superconductors, revealing unique current behaviors due to midgap states and confirming predictions with experimental data.

Contribution

It provides a theoretical analysis of magnetic field effects on Josephson tunneling in d-wave superconductors, highlighting the role of midgap states and predicting a distinct current-field dependence.

Findings

Current component from midgap states dominates in certain orientations.

The magnetic field dependence deviates from the conventional Fraunhofer pattern.

Critical current varies linearly with magnetic field for weak B.

Abstract

The magnetic field effect in the Josephson tunneling between two d-wave superconductors are investigated. When the crystal orientation of one (or each) superconductor relative to the interface normal is such that midgap states exist at the interface, there is a component of the tunneling current due to the midgap states. For a junction with a flat {001}|{110} or {100}|{110} interface, this component is the predominant contribution to the current. The predicted current-field dependence differs entirely from the conventional Fraunhofer pattern, in agreement with a published measurement. This is because, apart from the Fraunhofer factor, the critical current depends on the magnetic field B through the current density also which is a linear function of B for weak B.