Conductance via Multi orbital Kondo Effect in Single Quantum Dot

TL;DR

This paper investigates how multiple orbitals in a single quantum dot influence conductance through the Kondo effect, revealing distinct behaviors at zero and finite temperatures under magnetic fields.

Contribution

It provides a detailed analysis of multi-orbital Kondo effects on conductance using exact and approximate solutions, highlighting new magnetic field-dependent phenomena.

Findings

Conductance remains constant at zero temperature for two orbitals regardless of magnetic field.

Conductance increases at zero temperature with more orbitals, showing a maximum at finite temperatures.

Magnetic fields significantly alter conductance behavior depending on the number of orbitals.

Abstract

We study the Kondo effect in a single quantum dot system with two or three orbitals by using the Bethe-ansatz exact solution at zero temperature and the non-crossing approximation at finite temperatures. For the two-orbital Kondo effect, the conductance is shown to be constant at absolute zero in any magnetic fields, but decrease monotonically with increasing fields at finite temperatures. In the case with more orbitals, the conductance increases at absolute zero, while it features a maximum structure as a function of the magnetic field at finite temperatures. We discuss how these characteristic transport properties come from the multi orbital Kondo effect in magnetic fields.