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arXiv · 1407.5006

Fractional Quantum Hall Effect in a Diluted Magnetic Semiconductor

C. Betthausen·P. Giudici·A. Iankilevitch·C. Preis·V. Kolkovsky·M. Wiater·G. Karczewski·B. A. Piot·J. Kunc·M. Potemski·T. Wojtowicz·D. Weiss
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Abstract

We report the observation of the fractional quantum Hall effect in the lowest Landau level of a two-dimensional electron system (2DES), residing in the diluted magnetic semiconductor Cd(1-x)Mn(x)Te. The presence of magnetic impurities results in a giant Zeeman splitting leading to an unusual ordering of composite fermion Landau levels. In experiment, this results in an unconventional opening and closing of fractional gaps around filling factor v = 3/2 as a function of an in-plane magnetic field, i.e. of the Zeeman energy. By including the s-d exchange energy into the composite Landau level spectrum the opening and closing of the gap at filling factor 5/3 can be modeled quantitatively. The widely tunable spin-splitting in a diluted magnetic 2DES provides a novel means to manipulate fractional states.

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C. Betthausen, P. Giudici, A. Iankilevitch, C. Preis, V. Kolkovsky, M. Wiater, G. Karczewski, B. A. Piot, J. Kunc, M. Potemski, T. Wojtowicz, D. Weiss. 2014-07-18. Fractional Quantum Hall Effect in a Diluted Magnetic Semiconductor. https://doi.org/10.1103/physrevb.90.115302

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