title: Spectroscopy of few-electron collective excitations in charge-tunable artificial atoms.
abstract: We report the investigation of electronic excitations in InGaAs self-assembled quantum dots using resonant inelastic light scattering. The dots can be charged via a gate by N=1, em leader,6 electrons. We observe excitations, which are identified as transitions of electrons, predominantly from the s to the p shell (s-p transitions) of the quasiatoms. We find that the s-p transition energy decreases and the observed band broadens, when the p shell is filled with 1 to 4 electrons. By a theoretical model, which takes into account the full Coulomb interaction in the few-electron artificial atom, we can confirm the experimental results to be an effect of the Coulomb interaction in the quantum dot.
authors.affiliation: Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Brocke
authors.forename: M-T
authors.initials: MT
authors.lastname: Bootsmann
authors.forename: M
authors.initials: M
authors.lastname: Tews
authors.forename: B
authors.initials: B
authors.lastname: Wunsch
authors.forename: D
authors.initials: D
authors.lastname: Pfannkuche
authors.forename: Ch
authors.initials: Ch
authors.lastname: Heyn
authors.forename: W
authors.initials: W
authors.lastname: Hansen
authors.forename: D
authors.initials: D
authors.lastname: Heitmann
authors.forename: C
authors.initials: C
authors.lastname: Schüller