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SUMMARY:Multicomponent Skyrmion lattices and their excitations - Dr Dimitr
 y Kovrizhin\, Imperial College London
DTSTART:20121101T141500Z
DTEND:20121101T151500Z
UID:TALK41298@talks.cam.ac.uk
CONTACT:Dr G Moller
DESCRIPTION:\nWe study quantum Hall ferromagnets with a finite density top
 ologically\ncharged spin textures in the presence of internal degrees of f
 reedom\nsuch as spin\, valley\, or layer indices\, so that the system is\n
 parametrised by a N-component complex spinor field. In the absence of\nani
 sotropies\, we find formation of a hexagonal Skyrmion lattice which\ncompl
 etely breaks the underlying SU(N) symmetry. We compute analytically\nthe c
 omplete low-lying excitation spectrum\, which separates into N^{2}-1\ngapl
 ess acoustic magnetic modes and a magnetophonon. We discuss the role\nof e
 ffective mass anisotropy for SU(3)-valley Skyrmions relevant for\nexperime
 nts with AlAs quantum wells. Here\, we find a transition\, which\nbreaks a
  six-fold rotational symmetry of a triangular lattice\, followed by\na for
 mation of a square lattice at large values of anisotropy strength.\n\nD. L
 . Kovrizhin\, Benoît Douçot\, R. Moessner\, arXiv:1207.4021.
LOCATION:TCM Seminar Room\, Cavendish Laboratory
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