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

Abstract

Encouraged by 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 biases the Kondo conductance zero-bias anomaly is scaled by the Kondo temperature to a universal line shape predicted by the numerical study. The line shape can be approximated by a phenomenological expression of a single argument $e{V}_{\mathrm{sd}}/{k}_{\mathrm{B}}{T}_{\mathrm{K}}$. The knowledge of an analytical expression for the line shape provides an alternative way to estimate the Kondo temperature in a real experiment, with no need for time-consuming temperature dependence measurements of the linear conductance.