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arXiv · 1108.2961

Evidence for universal conductance correction in a tunable strongly coupled nanogranular metal

Roland Sachser·Fabrizio Porrati·Christian H. Schwalb·Michael Huth
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Abstract

We present temperature-dependent conductivity data obtained on a sample set of nanogranular Pt-C with finely tuned inter-grain tunnel coupling strength g. For samples in the strong-coupling regime g > g_C, characterized by a finite conductivity for T -> 0, we find a logarithmic behavior at elevated temperatures and a crossover to a sqrt(T)-behavior at low temperatures over a wide range of coupling strengths g_C = 0.25 < g <= 3. The experimental observation for g > 1 is in very good agreement with recent theoretical findings on ordered granular metals in three spatial dimensions. The results indicate a validity of the predicted universal conductivity behavior that goes beyond the immediate range of the approach used in the theoretical derivation.

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Roland Sachser, Fabrizio Porrati, Christian H. Schwalb, Michael Huth. 2011-08-15. Evidence for universal conductance correction in a tunable strongly coupled nanogranular metal. https://doi.org/10.1103/physrevlett.107.206803

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