Quantum hopping in doped conducting polymers

V. N. Prigodin(a) and A. J. Epstein(a,b)

(a) Department of Physics and (b) Department of Chemistry
The Ohio State University
Columbus, OH, 43210-1106 USA

Metallic doped polymers (polyaniline and polypyrrole) have an electromagnetic response [1,2] that, when analyzed within the standard theory of metals, is provided by an extremely small fraction of the total number of available electrons ~ 0.1 % (in contrast to ~ 100 % for common metals such as Cu, Ag, Al, or Ni) but with anomalous long scattering time > 10-13 s (~ 100 times longer than for common metals). We show that a network of metallic grains (the polymer's crystalline domains) connected by resonance quantum tunneling through strongly localized states in surrounding disordered medium produces this behavior. The small fraction of electrons is assigned to the low density of resonance states and the long scattering time is related to the narrow width of energy levels in resonance.

Supported in part by ONR


1. R. S. Kohlman et al., Phys. Rev. Lett. 78, 3915 (1997).
2. H. C. F. Martens et al., Phys. Rev. B 63, 07203 (2001).