Regensburg 2004 – wissenschaftliches Programm
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MA: Magnetismus
MA 27: Spinabh
ängiger Transport II
MA 27.14: Vortrag
Donnerstag, 11. März 2004, 18:30–18:45, H22
Anomalous Hall effect and Berry Phase in Ferromagnets — •Mathieu Taillefumier1,2, Vitalii Dugaev1,3, and Patrick Bruno1 — 1Max Planck Institut für mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany — 2Laboratoire Louis Néel, CNRS, Boite Postale 166,, 38042 Grenoble Cedex 09, France — 3Institute for Problems of Materials Science, NASU, Vilde 5, 58001 Chernovtsy, Ukraine
We propose a new mechanism of anomalous Hall effect (AHE) in two-dimensional ferromagnets and magnetic nanostructures with inhomogeneous magnetization. In contrast to the usual theories (side jump and skew scattering mechanism) of AHE, the presented theory does not necessary require spin-orbit interaction, and is induced by a Berry phase of the wavefunctions of the electrons moving a inhomogeneous magnetization field. We obtain a nonvanishing contribution to the Hall conductivity provided that the topology of the magnetization field is nontrivial like in the case of separated magnetic domains or periodic lattice of magnetic domains.
We propose an experiment with a structure containing two-dimensional electrons or holes of diluted magnetic semiconductor subject to the stray field of a lattice of magnetic nanocylinders. The striking behavior predicted for such a system (of which all revelant parameters are well known) allows to distinguish it from the other mechanisms.