INHOMOGENEOUS DISORDER AND THE MODIFIED DRUDE METALLIC STATE OF CONDUCTING POLYMERS

The metallic state of the very highly conducting doped polymers, such as polyacetylene, polypyrrole and polyaniline, is shown to have remark able similarities. Though each of these doped polymers has a different temperature-dependent conductivity, each of these doped polymer syste ms has a similar metal-like, Pauli susceptibility and density of state s at the Fermi level. Also, each of these highly conducting systems di splays a universal electronic response (dielectric constant and conduc tivity) as a function of frequency from the microwave regime (10(9) Hz ) through to the 'all conduction electron plasma frequency' (1 to 3 eV , depending on the polymer). This common behavior despite apparent dif ferences in the temperature-dependent conductivities is proposed to be a consequence of the inhomogeneous crystalline order in these materia ls, leading to three-dimensional metallic domains or islands (crystall ographically coherent regions), separated by poorly conducting weak li nks (disordered regions and interfiber links).