Evolution of the Kondo effect in a quantum dot probed by shot noise

Phys Rev Lett. 2011 Apr 29;106(17):176601. doi: 10.1103/PhysRevLett.106.176601. Epub 2011 Apr 26.

Abstract

We measure the current and shot noise in a quantum dot in the Kondo regime to address the nonequilibrium properties of the Kondo effect. By systematically tuning the temperature and gate voltages to define the level positions in the quantum dot, 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 noninteracting model, reaching 1.8±0.2.