Nonlinear Conductivity and Noise due to Charge-Density-Wave Depinning in Nb<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Se</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Abstract

A simple model for the depinning and dynamics of a sliding charge-density wave is presented. The model consists of viscously damped motion in a periodic potential and accounts for the main features of the nonlinear conductivity, noise, and ac-dc coupling in the charge-density-wave state of Nb${\mathrm{Se}}_{3}$ at low temperature. Comparison with experimental data suggests that the depinning process is associated with the displacement of the charge-density wave by approximately one period $\ensuremath{\lambda}$.