Defect Interactions and Noise in Metallic Nanoconstrictions

Abstract

Two-level resistance fluctuations have been observed in clean metallic constrictions of sizes 40-8000 ${\mathrm{nm}}^{3}$. At low temperatures the measured values for the activation energies, attempt frequencies, and scattering cross-section changes of such two-level fluctuations suggest that we are observing defects moving between metastable configurations. The strength of observed interactions between fluctuations has been estimated. At high temperatures interactions dominate the noise dynamics, causing complex fluctuations that evolve slowly in time to produce a $\frac{1}{f}$ noise spectrum.