Andreev tunnelling in quantum dots: A slave-boson approach

TL;DR

This paper investigates how Andreev tunneling affects quantum dots connected to normal and superconducting leads, revealing an enhancement of the Kondo resonance due to resonant Andreev scattering at low temperatures.

Contribution

It introduces a slave-boson approach to analyze the interplay of Kondo effect and superconductivity in quantum dots, highlighting the enhancement of zero bias anomalies.

Findings

Zero bias anomaly is enhanced by superconductivity.

Resonant Andreev scattering amplifies the Kondo resonance.

Slave-boson technique effectively models low-temperature transport.

Abstract

We study a strongly interacting quantum dot connected to a normal and to a superconducting lead. By means of the slave-boson technique we investigate the low temperature regime and discuss electrical transport through the dot. We find that the zero bias anomaly in the current-voltage characteristics which is associated to the occurance of the Kondo resonance in the quantum dot, is enhanced in the presence of superconductivity, due to resonant Andreev scattering.