Quantum hopping in metallic polymers

• Published in: Physica. B, Condensed matter Vol. 338; no. 1; pp. 310 - 317
• Main Authors: Prigodin, V.N., Epstein, A.J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2003; Elsevier
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conducting polymers; Conductivity phenomena in semiconductors and insulators; Electrical, magnetic and optical properties; Electronic transport in condensed matter; Exact sciences and technology; Granular model; Metallic states; Mixed conductivity and conductivity transitions; Mobility edges ; hopping transport; Organic polymers; Physicochemistry of polymers; Physics; Properties and characterization; Quantum dots; Quantum transport; Resonance tunneling; Conducting polymers; Resonance tunneling; 73.20.Jc; Metallic states; Quantum dots; 72.80.Le; Quantum transport; Granular model; 72.10Bg; Frequency dependence; 73.20.Jc Quantum transport; Electrical conductivity; Drude model; Metal-insulator transition; Theoretical study; Electron delocalization; Resonant tunnelling; Hopping conduction; Permittivity
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2003.08.011

Highly conducting polymers such as polyaniline and polypyrrole in a metallic state have unusual frequency-dependent conductivity, including multiple zero crossing of the dielectric function. A low-frequency electromagnetic response in terms of a Drude metal is provided by an extremely small fraction of the total number of conduction electrons ∼0.1% but with extremely high mobility or anomalously long scattering time ∼10 −13 s. We show that a network of metallic grains connected by resonance quantum tunneling has a Drude-type response for both the high- and low-frequency regimes and behaves as a dielectric at intermediate frequency in agreement with experimental observations. The metallic grains in polymers represent crystalline domains of well-packed chains with delocalized electrons embedded in the amorphous media of poor chain order. Intergrain resonance tunneling occurs through the strongly localized states in the amorphous media.