NONLINEAR DYNAMICS OF CHARGE-DENSITY-WAVE IN ORTHORHOMBIC TAS3 AT MICROWAVES

Non-linear dc and microwave conductivity due to collective transport of charge-density-wave in TaS3 was experimentally investigated at T = 78-215 K. The non-linear dc field dependence of a differential conductivity dI/dV exhibits a threshold field E(T1) sharply defined in the temperature range of 140-215 K. As the temperature decreases beyond 140 K the field E(T1) disappears, and the second threshold field E(T2) much greater than E(T1) originates. The two fields are temperature dependent and show decreasing under a microwave radiation. A non-linear response V(OMEGA) to the microwave radiation was observed at T = 78-215 K in a mixing experiment (detuned Case, OMEGA = omega-1 - omega-2 is not identically equal to 0). The dc field dependencies of the non-linear response V(OMEGA) reveal no signs of the threshold field singularities. The experimental results have been satisfactorily described by a classical model of an overdamped oscillator by introducing an empirical distribution function for the threshold field and by averaging V(OMEGA) over E(T).