We report on a complex nontrivial behavior of the optical anisotropy of quantum dots that is induced by a magnetic field in the plane of the sample. We find that the optical axis either rotates in the opposite direction to that of the magnetic field or remains fixed to a given crystalline direction. A theoretical analysis based on the exciton pseudospin Hamiltonian unambiguously demonstrates that these effects are induced by isotropic and anisotropic contributions to the heavy-hole Zeeman term, respectively. The latter is shown to be compensated by a built-in uniaxial anisotropy in a magnetic field B_c = 0.4 T, resulting in an optical response typical for symmetric quantum dots.
@article{arxiv.cond-mat/0601270,
title = {Anomalous in-plane magneto-optical anisotropy of self-assembled quantum dots},
author = {T. Kiessling and A. V. Platonov and G. V. Astakhov and T. Slobodskyy and S. Mahapatra and W. Ossau and G. Schmidt and K. Brunner and L. W. Molenkamp},
journal= {arXiv preprint arXiv:cond-mat/0601270},
year = {2009}
}