Three-orbital Kondo effect in single quantum dot system with plural electrons

TL;DR

This paper investigates the three-orbital Kondo effect in multi-electron quantum dots, analyzing how orbital degeneracy, Coulomb interactions, and magnetic fields influence transport properties like conductance and thermopower.

Contribution

It introduces a detailed three-orbital Anderson impurity model with realistic effects and explores the impact of orbital splitting on the Kondo effect in quantum dots.

Findings

Orbital degeneracy significantly affects conductance and thermopower.

Magnetic fields modulate the Kondo temperature and transport limits.

Orbital splitting alters the symmetry and transport behavior.

Abstract

We study the Kondo effect and related transport properties in orbitally degenerate vertical quantum dot systems with plural electrons. Applying the non-crossing approximation to the three-orbital Anderson impurity model with the finite Coulomb interaction and Hund-coupling, we investigate the magnetic-field dependence of the conductance and thermopower. We also introduce an additional orbital splitting to take account of the realistic many-body effect in the vertical quantum dot system. It is clarified how the three-orbital Kondo effect influences the transport properties via the modulation of the Kondo temperature and unitary limit of transport quantities due to the change of the symmetry in the system.