Field dependence of the non-linear conduction of charge-density waves in thallium blue bronze Tl_0.3MoO₃

The non-linear transport properties of sliding charge-density waves (CDWS) in pure Tl_0.3MoO₃ and impurity-doped (Tl _0.2K_0.8)_0.3MoO₃ blue bronzes are measured in the temperature range 80-150 K. It is found that the analytical form of non-linear current in a moderate field range fits the power-law relation, i.e. I_CDW varies as (V/V_r-1)^alpha, where the exponent alpha is temperature dependent and not a constant 1.5. Such a relation seems to be universal for blue bronzes over the temperature range below the Peierls transition temperature and does not depend on the quality of samples. The results are in agreement with those observed by Mihaly et al for pure K _0.3MoO₃ blue bronze in the low-temperature range and suggest that the dominant damping of the collective mode arises from the dissipative normal current induced by dynamical deformation of the CDWS, not only in the low-temperature range, but also in the high-temperature range.