engleski

Low-frequency dielectric response of charge-density wave pinned by commensurability in (2, 5(OCH_3)DCNQI)_2Li

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(OCH_3)DCNQI)_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 (epsilon_o = 3 imes 10^7) and the characteristic relaxation time ( au_o) are much larger than that expected for single particle excitations. au_o 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.

charge-density wave systems; collective modes

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