Spectroscopic signatures of many-body interactions and delocalized states in self-assembled lateral quantum dot molecules

TL;DR

This study uses optical spectroscopy to investigate the energy levels and many-body interactions in lateral quantum dot molecules, revealing molecular-like delocalized states for electrons in the excited shell.

Contribution

It provides experimental evidence of delocalized states and characterizes the energy structure of lateral quantum dot molecules under electric fields.

Findings

Identification of molecular-like delocalized states for electrons

Characterization of energy level structure and interactions

Spectral signatures of charging and many-body effects

Abstract

Lateral quantum dot molecules consist of at least two closely-spaced InGaAs quantum dots arranged such that the axis connecting the quantum dots is perpendicular to the growth direction. These quantum dot complexes are called molecules because the small spacing between the quantum dots is expected to lead to the formation of molecular-like delocalized states. We present optical spectroscopy of ensembles and individual lateral quantum dot molecules as a function of electric fields applied along the growth direction. The results allow us to characterize the energy level structure of lateral quantum dot molecules and the spectral signatures of both charging and many-body interactions. We present experimental evidence for the existence of molecular-like delocalized states for electrons in the first excited energy shell.