Josephson current through charge density waves

TL;DR

This paper theoretically investigates how the motion of charge density waves influences the Josephson current in superconductor-CDW-superconductor junctions, revealing oscillatory behavior and the role of collective modes.

Contribution

It introduces a kinetic model for superconductor-CDW systems, showing how CDW motion affects Josephson current and incorporating impurity pinning effects.

Findings

Below critical current, CDW remains stationary.

Above critical current, Josephson current oscillates with CDW velocity.

Collective modes act as non-linear shunting resistors.

Abstract

The effect of the collective charge density wave (CDW) motion on the Josephson current in a superconductor/charge density wave/superconductor junction is studied theoretically. By deriving the kinetic equations for the coupled superconductor-CDW system, it is shown that below the critical current the CDW does not move. Biased above this value, the Josephson current oscillates as a function of the velocity of the sliding CDW and the collective mode acts as a non-linear shunting resistor parallel to the Josephson channel. The effects of impurity pinning are accounted for at a phenomenological level.