Scaling behavior in the charge-density-wave conductivity of niobium triselenide

In the non-Ohmic regime the total differential conductivity of ${\mathrm{NbSe}}_3$ obeys a simple scaling relationship when the Ohmic conductivity ${\mathrm{\sigma }}_0$ is used as the scaling parameter, viz., dj(E,${\mathrm{\sigma }}_0$)/dE=g(${\mathrm{\sigma }}_0$)+f(${\mathrm{\sigma }}_0$ )E. This equation is valid for fields E varying from 2${\mathrm{E}}_{\mathrm{T}}$ up to 500${\mathrm{E}}_{\mathrm{T}}$ at 50 K (where ${\mathrm{E}}_{\mathrm{T}}$ is the threshold field). We have also verified it over the range of temperatures 50 K>T>15 K. Implications for the theory of charge-density-wave transport are discussed.