LOW-FREQUENCY ANOMALY AND QUASI-PARTICLE SCREENING IN SEMICONDUCTING CDW SYSTEMS AT LOW-TEMPERATURES

We analyze a one-dimensional model of a nonuniform charge-density wave presented in the form of a periodic chain of phase solitons interacting with defects. Taking into account screening by free charge carriers, we calculate the response of the system to a weak ac current. It is shown that the dielectric constant Re epsilon as a function of temperature T has a peak at low T and the dependence of epsilon on the frequency omega and impurity content agrees qualitatively with experimental data.