Abstract
We have used complex conductivity measurements between 20 Hz and 1 MHz to probe the dielectric response in the low-temperature phase of the (2,5(OCH3)2DCNQI)2Li organic conductor. The observed data reveal the existence of the relaxation process which is well described by a Debye-like expression for an overdamped response of a system with a single degree of freedom. Both the static dielectric constant (ε0 = 3 × 107) and the characteristic relaxation time (τ0) are much larger than that expected for single-particle excitations. τ0 is thermally activated in a manner similar to the dc conductivity. We attribute the observed relaxation to N = 4 charge density wave pinned by commensurability to the underlying lattice.