Interplay between disorder and quasi-regularity in CDW systems

Abstract.- We develop here a microscopical model of quasi-regular impurity distri-bution driven by the CDW appropriate for highly mobile impurities or materials with fictitious CDW transition temperature. Thermal hysteresis effects a t the CDW transi-tion reported in the quasi-1D materials NbSe3 and TazNiSe-, could be interpreted in the framework of the present model. Possible connections with other (alloy, heavy-fermion) systems are also suggested. 1 Introduction. The displacive motion of the impurities immersed into the one-dimensional system has been studied in detail previously as one kind of quasi-regularity driven by CDW [I]. As a further investigation of this problem we develop here a microscopical model for a different kind of quasi-regular impurity distribution driven by the CDW, consisting of the modulation in the probability of occupied sites