Coulomb effects in tunneling through a quantum dot stack

TL;DR

This paper investigates how Coulomb interactions influence electron tunneling through a vertically coupled quantum dot system, analyzing experimental current-voltage features with a master equation model that captures coherent and incoherent effects.

Contribution

It introduces a Pauli master equation approach to model Coulomb effects in quantum dot tunneling, providing insights into double-peak phenomena and the interplay of coherence and incoherence.

Findings

Double peaks in current-voltage are explained by tunnel coupling and contact interactions.

The model accurately reproduces experimental tunneling features.

Coherent and incoherent effects are effectively described by the density matrix approach.

Abstract

Tunneling through two vertically coupled quantum dots is studied by means of a Pauli master equation model. The observation of double peaks in the current-voltage characteristic in a recent experiment is analyzed in terms of the tunnel coupling between the quantum dots and the coupling to the contacts. Different regimes for the emitter chemical potential indicating different peak scenarios in the tunneling current are discussed in detail. We show by comparison with a density matrix approach that the interplay of coherent and incoherent effects in the stationary current can be fully described by this approach.