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.
@article{arxiv.1112.2585,
title = {Highly Non-linear Excitonic Zeeman Spin-Splitting in Composition-Engineered Artificial Atoms},
author = {V. Jovanov and T. Eissfeller and S. Kapfinger and E. C. Clark and F. Klotz and M. Bichler and J. G. Keizer and P. M. Koenraad and M. S. Brandt and G. Abstreiter and J. J. Finley},
journal= {arXiv preprint arXiv:1112.2585},
year = {2012}
}