A new perturbation treatment applied to the transport through a quantum dot

TL;DR

This paper introduces a novel perturbation scheme for analyzing resonant tunneling through a quantum dot, accurately capturing weak and strong coupling limits and aligning well with experimental observations.

Contribution

A new perturbation approach for nonequilibrium transport in quantum dots that ensures correct limits and self-consistent impurity occupation.

Findings

Conductance matches exact sum rule at zero temperature.

Finite temperature conductance exhibits a minimum at the Kondo valley.

Bias voltage effects on density of states are discussed.

Abstract

Resonant tunnelling through an Anderson impurity is investigated by employing a new perturbation scheme at nonequilibrium. This new approach gives the correct weak and strong coupling limit in $U$ by introducing adjustable parameters in the self-energy and imposing self-consistency of the occupation number of the impurity. We have found that the zero-temperature linear response conductance agrees well with that obtained from the exact sum rule. At finite temperature the conductance shows a nonzero minimum at the Kondo valley, as shown in recent experiments. The effects of an applied bias voltage on the single-particle density of states and on the differential conductances are discussed for Kondo and non-Kondo systems.