Zero-bias anomalies in electrochemically fabricated nanojunctions

TL;DR

This paper introduces a simple electrochemical method to create metal nanojunctions and investigates their low-temperature conductance properties, revealing a zero-bias anomaly caused by density of states suppression.

Contribution

It presents a new fabrication technique for metal nanojunctions and links the zero-bias conductance suppression to density of states effects in the leads.

Findings

Zero-bias anomaly depends on fabrication chemistry and junction size

Suppression of conductance observed near zero-bias at low temperatures

Evidence suggests the anomaly is due to density of states suppression in leads

Abstract

A streamlined technique for the electrochemical fabrication of metal nanojunctions (MNJs) between lithographically defined electrodes is presented. The first low-temperature transport measurements in such structures reveal suppression of the conductance near zero-bias. The size of the zero-bias anomaly (ZBA) depends strongly on the fabrication electrochemistry and the dimensions of the resulting MNJ. We present evidence that the nonperturbative ZBA in atomic-scale junctions is due to a density of states suppression in the leads.