Nonequilibrium conductance of asymmetric nanodevices in the Kondo regime

TL;DR

This paper investigates how the conductance coefficient in Kondo nanodevices depends on lead-dot coupling ratios, revealing that in the strong coupling regime, this dependence vanishes due to suppressed charge fluctuations.

Contribution

It provides new insights into the behavior of the conductance coefficient in asymmetric Kondo systems, especially in the strong coupling regime.

Findings

Dependence of the conductance coefficient on lead-dot coupling ratios disappears in the strong coupling regime.

Charge fluctuations of the impurity vanish in the strong coupling Kondo regime.

Analytic expressions for the scaling function are consistent with experimental observations.

Abstract

The scaling properties of the conductance of a Kondo impurity connected to two leads that are in or out of equilibrium has been extensively studied, both experimentally and theoretically. From these studies, a consensus has emerged regarding the analytic expression of the scaling function. The question addressed in this brief report concerns the properties of the experimentally measurable coefficient $\alpha$ present in the term describing the leading dependence of the conductance on $eV/T_K$, where $V$ is the source-drain voltage and $T_K$ the Kondo temperature. We study the dependence of $\alpha$ on the ratio of the lead-dot couplings for the particle-hole symmetric Anderson model and find that this dependence disappears in the strong coupling Kondo regime in which the charge fluctuations of the impurity vanish.