Josephson Current through Charge Density Waves

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 nonlinear shunting resistor parallel to the Josephson channel. Internal mode locking of the Josephson and CDW frequencies causes oscillations in the current-voltage characteristics and plateaus in the CDW conductance. copyright 1997 The American Physical Society