Weak Localization in Metallic Granular Media

Abstract

We investigate the interference correction to the conductivity of a medium consisting of metallic grains connected by tunnel junctions. Tunneling conductance between the grains, $e^2{g}_{\mathrm{T}}/\pi \hslash$, is assumed to be large, $g_{\mathrm{T}}\gg 1$. We demonstrate that the weak localization correction to conductivity exhibits a crossover at temperature $T\sim g_{\mathrm{T}}^2\delta$, where $\delta$ is the mean level spacing in a single grain. At the crossover, the phase relaxation time determined by the electron-electron interaction becomes of the order of the dwell time of an electron in a grain. Below the crossover temperature, the granular array behaves as a continuous medium, while above the crossover the weak localization effect is largely a single-junction phenomenon. We elucidate the signatures of the granular structure in the temperature and magnetic field dependence of the weak localization correction.

8 pages, 4 figures. Considerable modifications mostly related to the derivation of WL correction in granular medium

References in corpus (9)

• Quantum Transport in Semiconductor Nanostructures
• Quantum Effects in Coulomb Blockade
• Dephasing of Electrons in Mesoscopic Metal Wires
• Transport properties of granular metals at low temperatures
• Entangled electron current through finite size normal-superconductor tunneling structures
• Inelastic Scattering Time for Conductance Fluctuations
• Universal Description of Granular Metals at Low Temperatures: Granular Fermi Liquid
• Weak localization effects in granular metals
• Quantum Charge Fluctuations in a Superconducting Grain

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• Fluctuation spectroscopy of granularity in superconducting structures
• Hall Transport in Granular Metals and Effects of Coulomb Interactions
• Temperature and magnetic-field dependence of the quantum corrections to the conductance of a network of quantum dots
• Subgap tunneling via quantum-interference effect: insulators and charge density waves
• Gate voltage tuned quantum superconductor to insulator transition in an ultrathin bismuth film revisited