Nanomechanical characterization of the Kondo charge dynamics in a carbon nanotube

TL;DR

This study uses nanomechanical resonance of a suspended carbon nanotube to investigate Kondo charge dynamics in a quantum dot, revealing charge behavior and conductance characteristics consistent with Kondo models.

Contribution

It demonstrates a novel nanomechanical approach to probe Kondo correlations and charge dynamics in quantum dots, providing insights into charge behavior under strong Kondo effects.

Findings

Charge behavior is similar for odd and even quantum dot occupation.

Sequential tunneling models describe time-averaged charge despite Kondo conductance.

Temperature affects the shift in gate potentials for maximum current.

Abstract

Using the transversal vibration resonance of a suspended carbon nanotube as charge detector for its embedded quantum dot, we investigate the case of strong Kondo correlations between a quantum dot and its leads. We demonstrate that even when large Kondo conductance is carried at odd electron number, the charging behaviour remains similar between odd and even quantum dot occupation. While the Kondo conductance is caused by higher order processes, a sequential tunneling only model can describe the time-averaged charge. The gate potentials of maximum current and fastest charge increase display a characteristic relative shift, which is suppressed at increased temperature. These observations agree very well with models for Kondo-correlated quantum dots.