Hopping conductivity of a suspension of flexible wires in an insulator

Abstract

We study the hopping conductivity in a composite made of Gaussian coils of flexible metallic wires randomly and isotropically suspended in an insulator at such concentrations that the spheres containing each wire overlap. Uncontrolled donors and acceptors in the insulator lead to random charging of wires and, hence, to a finite density of states (DOS) at the Fermi level. Then the Coulomb interactions between electrons of distant wires result in the soft Coulomb gap. At low temperatures the conductivity is due to variable range hopping of electrons between wires and obeys the Efros-Shklovskii (ES) law $\ln \sigma \propto -(T_{ES}/T{)}^{1/2}$ with $T_{ES}$ decreasing with concentration and length of the wires. Due to enhanced screening of Coulomb potentials, at large enough wire concentrations and sufficiently high temperatures, the ES law is replaced by the Mott law $\ln \sigma \propto -(T_M/T{)}^{1/4}$.

arXiv comment5 pages, 4 figures

References in corpus (8)

• Density of States and Conductivity of Granular Metal or Array of Quantum Dots
• Variable-range hopping in quasi-one-dimensional electron crystals
• Localization, Coulomb interactions and electrical heating in single-wall carbon nanotubes/polymer composites
• Coulomb effects and hopping transport in granular metals
• Variable range cotunneling and conductivity of a granular metal
• Hopping conductivity of a suspension of nanowires in an insulator
• Coulomb blockade and transport in a chain of one-dimensional quantum dots
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Cited by in corpus (2)

• Solution of the tunneling-percolation problem in the nanocomposite regime
• Anisotropy in electrical conductivity of two-dimensional films containing aligned rodlike particles: continuous and lattice models