Universal out-of-equilibrium Transport in Kondo-correlated quantum dots: Renormalized dual Fermions on the Keldysh contour

TL;DR

This paper develops a novel dual fermion approach on the Keldysh contour to accurately model out-of-equilibrium transport in Kondo-correlated quantum dots, explaining sample-dependent conductance measurements.

Contribution

It introduces a new superperturbation theory using dual fermions for Kondo systems, capturing low-temperature transport behavior beyond symmetric models.

Findings

The method accurately reproduces experimental conductance data.

It explains sample dependence in Kondo transport measurements.

The approach extends theoretical understanding of out-of-equilibrium Kondo physics.

Abstract

The nonlinear conductance of semiconductor heterostructures and single molecule devices exhibiting Kondo physics has recently attracted attention. We address the observed sample dependence of the measured steady state transport coefficients by considering additional electronic contributions in the effective low-energy model underlying these experiments that are absent in particle-hole symmetric setups. A novel version of the superperturbation theory of Hafermann et al. in terms of dual fermions is developed, which correctly captures the low-temperature behavior. We compare our results with the measured transport coefficients.