Highly Non-linear Excitonic Zeeman Spin-Splitting in   Composition-Engineered Artificial Atoms
  Non-linear Zeeman splitting of neutral excitons is observed in composition engineered In(x)Ga(1-x)As self-assembled quantum dots and its microscopic origin is explained. Eight-band k.p simulations, performed using realistic dot parameters extracted from cross-sectional scanning tunneling microscopy, reveal that a quadratic contribution to the Zeeman energy originates from a spin dependent mixing of heavy and light hole orbital states in the dot. The dilute In-composition (x<0.35) and large lateral size (40-50 nm) of the quantum dots investigated is shown to strongly enhance the non-linear excitonic Zeeman gap, providing a blueprint to enhance such magnetic non-linearities via growth engineering. 
V. Jovanov, T. Eissfeller, S. Kapfinger, E. C. Clark, F. Klotz, M.   Bichler, J. G. Keizer, P. M. Koenraad, M. S. Brandt, G....
cond-mat.mes-hall