Kondo effect in carbon nanotube quantum dot in a magnetic field

TL;DR

This paper investigates the Kondo effect in a carbon nanotube quantum dot under magnetic fields, revealing complex splitting patterns in electron transport due to spin and orbital interactions.

Contribution

It provides a detailed analysis of the out-of-equilibrium Kondo effect in carbon nanotube quantum dots using non-equilibrium Green functions, highlighting magnetic field orientation effects.

Findings

Parallel magnetic field causes four-peak splitting of the Kondo resonance.

Perpendicular magnetic field results in a triple-peak density of states structure.

Orbital and spin fluctuations are distinctly reflected in the spectral features.

Abstract

The out-of-equilibrium electron transport of carbon nanotube semiconducting quantum dot placed in a magnetic field is studied in the Kondo regime by means of the non-equilibrium Green functions. The equation of motion method is used. For parallel magnetic field the Kondo peak splits in four peaks, following the simultaneous splitting of the orbital and spin states. For perpendicular field orientation the triple peak structure of density of states is observed with the central peak corresponding to orbital Kondo effect and the satellites reflecting the spin and spin-orbital fluctuations.