Effect of Exchange-type Zero-bias Anomaly on Single Electron Tunnelling of Au Nanoparticles

TL;DR

This study investigates how exchange-type zero-bias anomalies influence single electron tunnelling in gold nanoparticles, revealing a characteristic conductance gap and discrete tunnelling peaks explained by electron exchange interactions.

Contribution

It provides new experimental evidence and theoretical explanation for the impact of exchange interactions on tunnelling spectra of Au nanoparticles.

Findings

Observed a conductance gap of ~2e/C around zero bias.

Detected discrete tunnelling peaks with widths of ~e/C.

Exchange interactions suppress zero-bias tunnelling peaks.

Abstract

Using cryogenic scanning tunnelling microscopy and scanning tunnelling spectroscopy we measured single electron tunnelling of isolated Au nanoparticles with 1.4 nm in radius. We observe that a gap {\Delta}V ~ 2e/C (C is the capacitance of the Au particle) around zero bias in the tunnelling conductance spectrum, followed by a series of discrete single electron tunnelling peaks with voltage widths of EC ~ e/C at both negative and positive bias. Experimental data are well explained by taking into account the effect of exchange interaction of electrons on the single electron tunnelling of Au nanoparticles. A tunnelling peak near zero-bias was suppressed by the exchange-type zero-bias anomaly, which results in the gap {\Delta}V ~ 2EC.