Current-voltage relation for superconducting d-wave junctions

TL;DR

This paper calculates the current-voltage characteristics of d-wave superconducting junctions, revealing how midgap states influence conductance and can cause negative differential conductance and lowered threshold voltages.

Contribution

It provides a comprehensive analysis of I-V relations in d-wave junctions considering arbitrary orientations and transmissions, highlighting the role of midgap states.

Findings

Midgap states significantly affect I-V characteristics.

Negative differential conductance observed in certain configurations.

Resonant conduction through midgap states lowers threshold voltage.

Abstract

We calculate the current-voltage (I-V) relation for planar superconducting d-wave junctions for both arbitrary transmission of the junction and arbitrary orientation of the d-wave superconductors. The midgap states (MGS) present at interfaces/surfaces of a d-wave superconductor influence the I-V relation. In some arrangements we find considerable negative differential conductance and lower threshold voltage for non-zero current due to resonant conduction through MGS.