Tunneling Theory of Charge-Density-Wave Depinning

Introduction of a correlation length into the tunneling theory of depinning of charge-density waves by an electric field leads to a threshold field and to an expression for non-Ohmic conductivity in excellent agreement with experiments on the linear-chain compounds Nb${\mathrm{Se}}_3$ and Ta${\mathrm{S}}_3$. An extension of the theory leads to results for the frequency dependence of the ac conductivity, also in agreement with experiment.