Spin Fine Structure in Optically Excited Quantum Dot Molecules

TL;DR

This paper investigates the spin interactions in coupled quantum dot molecules, revealing fine structure patterns in optical spectra that are explained by molecular spin exchange, Pauli exclusion, and tunneling effects, advancing quantum spin control.

Contribution

It provides a detailed understanding of spin fine structure in quantum dot molecules and links optical spectra features to underlying spin interactions, enabling optical spin coupling.

Findings

Distinct fine structure patterns observed in optical spectra.

Spin exchange interactions and tunneling explain the fine structure.

Potential for optical control of spin states in quantum dots.

Abstract

The interaction between spins in coupled quantum dots is revealed in distinct fine structure patterns in the measured optical spectra of InAs/GaAs double quantum dot molecules containing zero, one, or two excess holes. The fine structure is explained well in terms of a uniquely molecular interplay of spin exchange interactions, Pauli exclusion and orbital tunneling. This knowledge is critical for converting quantum dot molecule tunneling into a means of optically coupling not just orbitals, but spins.