Low-frequency dielectric spectroscopy of commensurate density waves

Abstract

We overview complex conductivity measurements (20Hz - lMHz) in low-dimensional organic systems κ-(BEDT-TTF) 2 -Cu[N(CN) 2 ]Cl, and deuterated Cu-DCNQI and its alloys, with commensurate density wave ground states. We discuss the obtained results in comparison with those for the incommensurate density waves, like in (TMTSF) 2 PF 6 , in which the phason relaxation in a disordered background dominates. We show that in the commensurate systems with a random domain structure charged domain walls provide a more appropriate description of the observed dielectric relaxation.