Universal lineshape of the Kondo zero-bias anomaly in a quantum dot

TL;DR

This paper demonstrates that the zero-bias anomaly in Kondo conductance for a quantum dot exhibits a universal lineshape scaled by the Kondo temperature, validated by experiments and theoretical predictions, enabling easier estimation of T_K.

Contribution

The study confirms the universal lineshape of the Kondo zero-bias anomaly and provides an analytical expression for it, simplifying the determination of the Kondo temperature.

Findings

Universal lineshape of Kondo conductance observed

Analytical expression matches experimental data

Simplifies estimation of Kondo temperature

Abstract

Encouraged by the recent real-time renormalization group results we carried out a detailed analysis of the nonequilibrium Kondo conductance observed in an InAs nanowire-based quantum dot and found them to be in excellent agreement. We show that in a wide range of bias the Kondo conductance zero-bias anomaly is scaled by the Kondo temperature to a universal lineshape predicted by the numerical study. The lineshape can be approximated by a phenomenological expression of a single argument $eV_{sd}=k_{\rm B}T_{\rm K}$. The knowledge of an analytical expression for the lineshape provides an alternative way for estimation of the Kondo temperature in a real experiment, with no need for time consuming temperature dependence measurements of the linear conductance.