Nonlinear magnetoresistance and charge-density-wave depinning at liquid-helium temperatures inNbSe3

The transverse magnetoresistance of ${\mathrm{NbSe}}_3$ has been measured at liquid-helium temperatures as a function of the dc bias. The amplitude of the Shubnikov–de Haas oscillations is greatly suppressed by the electric field before the charge-density wave becomes depinned. As soon as the nonlinear state has been reached, the charge-density wave remains in a metastable state even after the electric field is reduced to zero. These metastable states give rise to a huge increase of the magnetoresistance, a shift of the extrema of the Shubnikov–de Haas oscillations, and a decrease of the Fermi-surface cross sections.