Quantum nucleation of phase slip in charge-density-wave systems: Role of long-range Coulomb interactions

Phase-slip processes near electrical contacts are responsible for the nonlinear current-voltage characteristic in clean charge-density-wave systems. In the low-temperature regime near absolute zero, the phase slip is induced by dislocation-loop (DL) nucleation due to quantum tunneling. The quantum nucleation rate of the phase slip is calculated at zero temperature by taking account of the Coulomb interaction effect on the DL. It is shown that a large charging energy associated with the DL greatly reduces the nucleation rate in the low-bias regime. Consequently, the current-voltage characteristic. which is determined by the nucleation rate. is shifted to higher voltages compared with that in the absence of the Coulomb interaction. The voltage shift is of the order of V-th similar to gammahomega(p)/e (gamma: anisotropy constant, omega(p): plasma frequency in the normal state).