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Institut f. Physik FG Nanostrukturierte Materialien
Martin-Luther-Universitat Halle-Wittenberg
Von-Danckelmann-Platz 3, D-06120 Halle, Germany
Tel.: +49 345 55 25321
Fax.: +49 345 55 27034
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T. Kiessling, G.V. Astakhov, A.V. Platonov, S. Mahapatra, T. Slobodskyy, W. Ossau, G. Schmidt, K. Brunner, L.W. Molenkamp Optical studies of structural and magnetic anisotropies in epitaxial CdSe/ZnSe quantum dots Phys. Stat. Soli. (C) Current Topics in Solid State Physics 4 (9) (2015-02-24 13:43:04), 3324-3333
We summarize experimental studies on the optical polarization properties of MBE-grown shape-asymmetric self-assembled CdSe/ZnSe quantum dots (QDs). The zero magnetic field fine structure splitting of excitonic transitions in structurally anisotropic QDs gives rise to an effective linear-to-circular and circular-to-linear optical polarization conversion upon resonant excitation of the QD ensemble. The effect is qualitatively modelled in terms of a pseudospin formalism. Furthermore, we show how an in-plane magnetic field leads to a complex rotation behavior of the axis of the optical polarization. Our analysis based on the exciton pseudospin Hamiltonian unambiguously displays that these effects are induced by isotropic and anisotropic contributions to the heavy hole Zeeman term. Likewise we show that the latter mechanism can be used to tune the optical respone of shape-anisotropic QDs such that the optical polarization properties are equal to QDs of perfect D2d symmetry. http://onlinelibrary.wiley.com/doi/10.1002/pssc.200775417/abstract |
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