Coulomb interaction signatures in self-assembled lateral quantum dot molecules

TL;DR

This study investigates Coulomb interactions in self-assembled lateral quantum dot molecules using photoluminescence spectroscopy, revealing charge configurations, tunneling phenomena, and the effects of voltage control through combined experimental and computational methods.

Contribution

It provides experimental evidence of inter-dot electron tunneling and charge state control in lateral quantum dot molecules, supporting theoretical predictions.

Findings

Identification of discrete spectral lines corresponding to specific charge states

Evidence of inter-dot electron tunneling consistent with theoretical models

Voltage control enables manipulation of charge occupancy in quantum dot molecules

Abstract

We use photoluminescence spectroscopy to investigate the ground state of single self-assembled InGaAs lateral quantum dot molecules. We apply a voltage along the growth direction that allows us to control the total charge occupancy of the quantum dot molecule. Using a combination of computational modeling and experimental analysis, we assign the observed discrete spectral lines to specific charge distributions. We explain the dynamic processes that lead to these charge configurations through electrical injection and optical generation. Our systemic analysis provides evidence of inter-dot tunneling of electrons as predicted in previous theoretical work.