Conductance Fluctuations in a Metallic Wire Interrupted by a Tunnel Junction

TL;DR

This paper experimentally investigates conductance fluctuations in a metallic wire with a tunnel junction, revealing a proportional relationship between fluctuation variance and bias voltage, explained by a theoretical model involving phase breaking and diffusion.

Contribution

It provides the first experimental analysis of conductance fluctuations in a wire interrupted by a tunnel junction, linking voltage dependence to disorder effects.

Findings

Variance of fluctuations is proportional to bias voltage V.

Data aligns with a model involving phase breaking time and diffusion coefficient.

Experimental results support theoretical predictions of conductance behavior.

Abstract

The conductance fluctuations of a metallic wire which is interrupted by a small tunnel junction has been explored experimentally. In this system, the bias voltage V, which drops almost completely inside the tunnel barrier, is used to probe the energy dependence of conductance fluctuations due to disorder in the wire. We find that the variance of the fluctuations is directly proportional to V. The experimental data are consistently described by a theoretical model with two phenomenological parameters: the phase breaking time at low temperatures and the diffusion coefficient.