Impact of Coulomb interaction and Kondo effect on transport in quantum dots

TL;DR

This paper investigates how Coulomb interactions and the Kondo effect influence electronic transport in quantum dots, revealing a modified universal effective charge observable via shot noise measurements.

Contribution

It introduces a detailed analysis of Coulomb interaction effects on the Kondo regime in quantum dots, including a voltage-dependent modification of the effective charge.

Findings

Coulomb interactions significantly alter the universal effective charge e* in quantum dots.

The effective charge e* is reduced by a factor less than one and depends on voltage.

The study provides a method to measure these effects through shot-noise experiments.

Abstract

We examine the impact of Coulomb electron-electron interaction on transport in a junction with a quantum dot described by Kondo Hamiltonian. We analyze the Fermi liquid regime and consider the limit of zero temperature. With the help of Keldysh technique we calculate the non-linear current and shot noise as a function of applied voltage. We show that Coulomb interaction markable influences the universal effective charge of current-carrying particles e*=5/3e which can be measured in shot-noise experiments. The electron-electron interaction modifies this universal value by a factor (e*=5/3eF) which is less then one and also voltage dependent.