Evolution of the Kondo Effect in a Quantum Dot Probed by the Shot Noise

TL;DR

This study investigates the evolution of the Kondo effect in a quantum dot by measuring current and shot noise, revealing enhanced noise and Fano factor deviations below the Kondo temperature, indicating complex many-body interactions.

Contribution

It provides experimental insights into the non-equilibrium properties of the Kondo effect through shot noise measurements in a quantum dot system.

Findings

Shot noise increases as temperature drops below the Kondo temperature.

Fano factor exceeds unity, reaching approximately 1.8, indicating strong correlations.

Two-particle scattering processes become more prominent in the Kondo regime.

Abstract

We measure the current and shot noise in a quantum dot (QD) in the Kondo regime to address the non-equilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the QD, we observe an enhancement of the shot noise as temperature decreases below the Kondo temperature, which indicates that the two-particle scattering process grows as the Kondo state evolves. Below the Kondo temperature, the Fano factor defined at finite temperature is found to exceed the expected value of unity from the non-interacting model, reaching $1.8 \pm 0.2$.