Magneto-optical properties of charged excitons in quantum dots
  We present both experimental and theoretical results on the influence of a magnetic field on excitons in semiconductor quantum dots. We find a pronounced difference between the strong and weak confinement regimes. For weak confinement, the excitonic diamagnetic shift is strongly dependent on surplus charge, corresponding to a reversal in sign of the conventional diamagnetic shift for neutral excitons. In this limit, we argue that the optical properties of excitons with two or more extra electrons are fundamentally different to those of the neutral exciton and trion. 
A.O. Govorov, C. Schulhauser, D. Haft, A.V. Kalameitsev, A. Chaplik,   R.J. Warburton, K. Karrai, W. Schoenfeld, J.M. Garcia...