Voltage-controlled electron-hole interaction in a single quantum dot
  The ground state of neutral and negatively charged excitons confined to a single self-assembled InGaAs quantum dot is probed in a direct absorption experiment by high resolution laser spectroscopy. We show how the anisotropic electron-hole exchange interaction depends on the exciton charge and demonstrate how the interaction can be switched on and off with a small dc voltage. Furthermore, we report polarization sensitive analysis of the excitonic interband transition in a single quantum dot as a function of charge with and without magnetic field. 
A. H\"ogele, S. Seidl, M. Kroner, K. Karrai, M. Atat\"ure, J. Dreiser,   A. Imamoglu, R. J. Warburton, B. D. Gerardot, P. M....