Universal scaling in nonequilibrium transport through an Anderson impurity

TL;DR

This paper investigates the scaling behavior of conductance in quantum dot systems modeled by the Anderson impurity, revealing complex dependencies and aligning with experimental observations when valence fluctuations are considered.

Contribution

It introduces a non-equilibrium renormalized perturbation theory approach to analyze conductance scaling in Anderson models, highlighting the role of valence fluctuations.

Findings

No simple quadratic scaling in the Kondo limit.

Agreement with experiments when valence fluctuations are included.

Complex conductance dependence on temperature and bias voltage.

Abstract

Using non-equilibrium renormalized perturbation theory, we calculate the conductance G as a function of temperature T and bias voltage V for an Anderson model, suitable for describing transport properties through a quantum dot. For renormalized parameters that correspond to the extreme Kondo limit, we do not find a simple scaling formula beyond a quadratic dependence in T and V. However, if valence fluctuations are allowed, we find agreement with recent experiments.