Granular Effect on Electron Conduction in Discontinuous Metal Films

TL;DR

This paper reanalyzes previous findings on low-temperature conduction in thin metal films, attributing the observed resistance behavior to granularity effects, and supports this with new measurements on nanogranular films.

Contribution

It provides a new interpretation of anomalous conduction in thin films by emphasizing granularity effects, supported by experimental data on nanogranular films.

Findings

Logarithmic resistance increase due to granularity in discontinuous films

Confirmation of granularity effects through Pb-SiO2 nanogranular film measurements

Reinterpretation of earlier results on thin-film metal conduction

Abstract

We reanalyze the seminal work by Dolan and Osheroff [Phys. Rev. Lett. $\textbf{43}$, 721 (1979)] which reported anomalous low-temperature conduction of high-resistivity thin-film metal strips. We argue that the observed logarithmic increase of resistance with decreasing temperature in their 3-nm-thick Au-Pd strips be ascribed to the granularity effect on electron conduction in discontinuous metal films. This reanalysis is further supported by our measurements on conducting Pb$_x$(SiO$_2$)$_{1-x}$ nanogranular films, where $x$ is the volume fraction of Pb.