Anomalous Electrical Conduction and Negative Temperature Coefficient of Resistance in Nanostructured Gold Resistive Switching Films

We report on the observation of non-metallic electrical conduction, resistive switching, and a negative temperature coefficient of resistance in cluster-assembled nanostructured gold films above the electrical percolation and in strong-coupling regime, from room to cryogenic temperatures (24K). The structure of the films is characterized by an extremely high density of randomly oriented crystalline nanodomains, separated by grain boundaries. The observed behavior can be explained by considering space charge limited conduction and Coulomb blockade phenomena highlighting the influence of the high density of defects and grain boundaries on the localization of conduction electrons. Our findings have implications for a broad class of resistive switching systems based on random assemblies of nanoobjects.