We observe the low-lying excitations of a molecular dimer formed by two electrons in a GaAs semiconductor quantum dot in which the number of confined electrons is tuned by optical illumination. By employing inelastic light scattering we identify the inter-shell excitations in the one-electron regime and the distinct spin and charge modes in the interacting few-body configuration. In the case of two electrons a comparison with configuration-interaction calculations allows us to link the observed excitations with the breathing mode of the molecular dimer and to determine the singlet-triplet energy splitting.
@article{arxiv.1002.3114,
title = {Correlated electrons in optically-tunable quantum dots: Building an electron dimer molecule},
author = {Achintya Singha and Vittorio Pellegrini and Aron Pinczuk and Loren N. Pfeiffer and Ken W. West and Massimo Rontani},
journal= {arXiv preprint arXiv:1002.3114},
year = {2010}
}
Comments
RevTeX 4.0, 6 pages, 6 color PDF figures. Revised version including Supplementary Discussion of Wigner localisation (2 new figures + new version of Fig. 2). To appear in Physical Review Letters