Coulomb Interaction Effects on the Terahertz Photon-Assisted Tunneling through a InAs Quantum Dot

TL;DR

This paper theoretically investigates how Coulomb interactions influence terahertz photon-assisted tunneling in InAs quantum dots, explaining experimental results and predicting new observable peaks related to Coulomb effects.

Contribution

The study provides a theoretical model that explains experimental PAT peaks and predicts additional Coulomb-induced peaks in InAs quantum dots.

Findings

Main peaks match experimental data

Additional Coulomb-related peaks predicted

Coulomb interaction must exceed THz photon frequency for excited state resonance

Abstract

Recently, the terahertz (THz) photon-assisted tunneling (PAT) through a two-level InAs quantum dot (QD) has been successfully realized in experiment [Phys. Rev. Lett. {\bf 109}, 077401 (2012)]. The Coulomb interaction in this device is comparable with the energy difference between the two energy levels. We theoretically explore the effects of Coulomb interaction on the PAT processes and show that the main peaks of the experiment can be well derived by our model analysis. Furthermore, we find additional peaks, which were not addressed in the InAs QD experiment and may be further identified in experiments. In particular, we show that, to observe the interesting photon-induced excited state resonance in InAs QD, the Coulomb interaction should be larger than THz photon frequency.