title: Correlated electrons in optically tunable quantum dots: building an electron dimer molecule.
abstract: 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 intershell 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.
authors.affiliation: NEST, Istituto di Nanoscienze-CNR and Scuola Normale Superiore, Pisa 56127, Italy.
authors.forename: Achintya
authors.initials: A
authors.lastname: Singha
authors.forename: Vittorio
authors.initials: V
authors.lastname: Pellegrini
authors.forename: Aron
authors.initials: A
authors.lastname: Pinczuk
authors.forename: Loren N
authors.initials: LN
authors.lastname: Pfeiffer
authors.forename: Ken W
authors.initials: KW
authors.lastname: West
authors.forename: Massimo
authors.initials: M
authors.lastname: Rontani