Researchers map energy spectra of up to seven electrons in quantum dots

Researchers have mapped the energy spectra of up to seven electrons contained within gallium arsenide quantum dots, exceeding the capabilities of many existing spectroscopic techniques. The team, spanning the University of Sheffield, Johannes Kepler University Linz, and the University of Sussex, achieved this detailed mapping by utilizing nuclear spins as a non-invasive probe, circumventing the disruptive effects of traditional charge transport spectroscopy. Experiments on low-strain GaAs/AlGaAs epitaxial dots, as described by the authors, revealed anomalously fast nuclear spin diffusion, supported by first-principles modelling. This work uncovers few-electron states as a new operating regime for optically active quantum dots, offering a…