Bad Metals Made with Good-Metal Components

Abstract

We have grown thin stable films of a good metal, Ag, that have characteristics of bad metals: high resistivity, strong temperature dependence of resistivity, and lack of resistive saturation. For films of different thickness, the temperature-dependent resistance and the Hall effect resistance provide evidence that the apparent bad metallicity is a consequence of the microstructure of the film rather than the result of new physics. This microstructure, which we characterize with scanning probe techniques, occurs on length scales comparable to the mean free path, thereby changing the sign of the classical magnetoresistance from positive to negative.