Non-Kondo zero bias anomaly in electronic transport through an ultra-small Si quantum dot

TL;DR

This study investigates zero bias anomalies in ultra-small silicon quantum dots, revealing a non-Kondo origin for conductance enhancements at low temperatures, differing from behaviors observed in GaAs quantum dots.

Contribution

The paper reports the discovery of a zero bias anomaly in silicon quantum dots that does not originate from the Kondo effect, contrasting with prior observations in other materials.

Findings

Coulomb blockade is partially lifted at certain gate voltages.

Zero bias conductance is enhanced at low temperatures.

Magnetic field dependence differs from Kondo effect predictions.

Abstract

We have studied low-temperature single electron transport through ultra-small Si quantum dots. We find that at low temperatures Coulomb blockade is partially lifted at certain gate voltages. Furthermore, we observed an enhancement of differential conductance at zero bias. The magnetic field dependence of this zero bias anomaly is very different from the one reported in GaAs quantum dots, inconsistent with predictions for the Kondo effect.