Non-linear exciton spin-splitting in single InAs/GaAs self-assembled   quantum structures in ultrahigh magnetic fields
  We report on the magnetic field dispersion of the exciton spin-splitting and diamagnetic shift in single InAs/GaAs quantum dots (QDs) and dot molecules (QDMs) up to $B$ = 28 T. Only for systems with strong geometric confinement, the dispersions can be well described by simple field dependencies, while for dots with weaker confinement considerable deviations are observed: most importantly, in the high field limit the spin-splitting shows a non-linear dependence on $B$, clearly indicating light hole admixtures to the valence band ground state. 
A. Babinski, G. Ortner, S. Raymond, M. Potemski, M. Bayer, P.   Hawrylak, A. Forchel, Z. Wasilewski, and S. Fafard