Temperature-Gradient-Induced Open-Circuit Electric Currents in Charge-Density-Wave Condensates

We have induced nonlinear conduction and current oscillations in the charge-density-wave state of $o-\mathrm{Ta}{\mathrm{S}}_3$ in an open-circuit ($I=0\mathrm{}$) configuration using a temperature gradient to generate thermal voltages exceeding a threshold. The above features are associated with a current carried by the condensate which is compensated by a normal current in the opposite direction. Our experiments provide the first clear observation of decoupled motion of the condensed and uncondensed electrons in solids with a charge-density-wave ground state.