Kondo temperature of a quantum dot

TL;DR

This paper investigates how the Kondo temperature varies with gate voltage in a quantum dot, revealing that high-order tunneling processes significantly influence this dependence beyond traditional models.

Contribution

It demonstrates that the gate voltage dependence of the Kondo temperature cannot be explained by the standard Anderson impurity model, highlighting the role of high-order tunneling processes.

Findings

Dependence of Kondo temperature on gate voltage is affected by high-order tunneling.

Standard Anderson model does not fully describe the observed dependence.

High-order tunneling processes dominate when gate voltage is away from Coulomb valley center.

Abstract

We study the dependence of the Kondo temperature on the gate voltage in a strongly blockaded quantum dot with a small single-particle level spacing. We show that the dependence cannot be fitted to that of the Anderson impurity model with the gate voltage-independent level width. The effect originates in high-order tunneling processes, which make a dominant contribution to the exchange amplitude when the gate voltage is tuned away from the middle of the Coulomb blockade valley.