Nonlinear Hall effect inK0.3MoO3due to the sliding of charge-density waves

Hall-effect data for a Peierls semiconductor, the blue bronze ${\mathrm{K}}_{0.3}$Mo${\mathrm{O}}_3$, are reported both below and above the threshold electric field for the sliding of charge-density waves (CDW). The motion of the CDW alters the Hall voltage significantly and the data are fitted to a theoretical model whereby the motion of the CDW induces a "backflow" of normal electrons which causes a reduction in the Hall voltage. However there are difficulties in accounting for the magnitude of the observed effect as well as the magnitude of the low-field Hall coefficient. Therefore it is tentatively suggested that a two-fluid model may provide a better estimate of the number of normal electrons than that given by the usual one-dimensional semiconductor picture.