Theory of electronic transport through a triple quantum dot in the presence of magnetic field

TL;DR

This paper develops a theoretical model for electronic transport in a triple quantum dot system under a magnetic field, revealing how magnetic flux influences energy degeneracies and conductance features.

Contribution

It introduces a tight binding model to analyze magnetic field effects on degeneracies and conductance dips in triple quantum dots, highlighting periodicity related to flux quanta.

Findings

Magnetic field induces degeneracies in the energy spectrum.

Zero transmission and conductance dips occur at degeneracies.

Periodic conductance oscillations depend on the number of levels involved.

Abstract

Theory of electronic transport through a triangular triple quantum dot subject to a perpendicular magnetic field is developed using a tight binding model. We show that magnetic field allows to engineer degeneracies in the triple quantum dot energy spectrum. The degeneracies lead to zero electronic transmission and sharp dips in the current whenever a pair of degenerate states lies between the chemical potential of the two leads. These dips can occur with a periodicity of one flux quantum if only two levels contribute to the current or with half flux quantum if the three levels of the triple dot contribute. The effect of strong bias voltage and different lead-to-dot connections on Aharonov-Bohm oscillations in the conductance is also discussed.