Influences of broken time-reversal symmetry on the d.c. Josephson effects in d-wave superconductors

TL;DR

This paper investigates how broken time-reversal symmetry, caused by a subdominant s-wave component, affects the d.c. Josephson current in d-wave superconductors, revealing significant modifications to expected low-temperature behaviors.

Contribution

It provides a self-consistent calculation showing the impact of subdominant s-wave components on Josephson effects and the suppression of low-temperature current enhancement.

Findings

Suppression of d-wave pair potential near insulator has minimal effect.

Inducement of s-wave component breaks time-reversal symmetry.

Low-temperature Josephson current enhancement is strongly suppressed.

Abstract

In order to examine the influences of the spatial dependence of the pair potential, the d.c. Josephson current in d-wave superconductors is calculated using self-consistently determined pair potentials. The results show that the suppression of the d-wave pair potential near the insulator does not have serious effect on the properties of the Josephson current. On the other hand, drastic changes are obtained due to the inducement of a subdominant s-wave component, which spontaneously breaks time reversal symmetry. Especially, a rapid enhancement of the Josephson current at low temperature predicted in previous formulas is strongly suppressed.