Nanometer-Scale Metallic Grains Connected with Atomic-Scale Conductors

TL;DR

This paper presents a technique for connecting nanometer-scale gold grains with atomic-scale conductors, analyzing how contact resistance influences Coulomb blockade and conductance features, with results aligning with theoretical predictions.

Contribution

It introduces a method to connect metallic grains with atomic-scale contacts and studies the impact of contact resistance on quantum transport phenomena.

Findings

High-resistance devices show Coulomb blockade.

Low-resistance devices exhibit a zero-bias conductance dip.

Intermediate resistance devices display Coulomb staircase.

Abstract

We describe a technique for connecting a nanometer-scale gold grain to leads by atomic-scale gold point contacts. These devices differ from previous metallic quantum dots in that the conducting channels are relatively well-transmitting. We investigate the dependence of the Coulomb blockade on contact resistance. The high-resistance devices display Coulomb blockade and the low-resistance devices display a zero-bias conductance dip, both in quantitative agreement with theory. We find that in the intermediate regime, where the sample resistance is close to $h/e^2$, the I-V curve displays a Coulomb staircase with symmetric contact capacitances.