Hopping conductivity of a suspension of nanowires in an insulator

Abstract

We study the hopping conduction in a composite made of straight metallic nanowires randomly and isotropically suspended in an insulator. Uncontrolled donors and acceptors in the insulator lead to random charging of wires and hence finite bare density of states 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 $\ln \sigma \propto -(T_{ES}/T{)}^{1/2}$. We show that $T_{ES}\propto 1/(n{L}^3{)}^2$, where $n$ is the concentration of wires and $L$ is the wire length. Due to enhanced screening of Coulomb potentials, at large enough $n{L}^3$, the ES law is replaced by the Mott law.

arXiv comment5 pages, 5 figures

References in corpus (6)

• 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
• Conductivity of a suspension of nanowires in a weakly conducting medium

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