Dresden 2014 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 16: Focus Session: Dynamics, Topology, and Fractionalisation

TT 16.5: Topical Talk

Montag, 31. März 2014, 17:15–17:45, HSZ 01

Unwinding a Skyrmion Lattice: Emergent Monopoles in Chiral Magnets — •Achim Rosch — University of Cologne, Cologne, Germany

Small magnetic fields and thermal fluctuations stabilize lattices of magnetic whirls, so-called skyrmions, in chiral magnets. These skyrmions are characterized by a topological winding number and couple very efficiently to electric currents by Berry phases. The effect of these Berry phases can be described by emergent electromagnetic fields [1].

The skyrmion lattice can be destroyed by a change of magnetic field [2]. The associated change of the topology of the magnetic structure has to occur by singular magnetic configurations which act as sources and sinks of the emergent magnetic flux. Thereby they can be viewed as emergent magnetic monopols. Combining numerical simulations, magnetic force microscopy and neutron scattering [2], we investigate the signatures and the dynamics of a topological first-order phase transition driven by the creation of monopoles and antimonopoles.
T. Schulz, R. Ritz, A. Bauer, M. Halder, M. Wagner, C. Franz, and C. Pfleiderer, K. Everschor, M. Garst, and A. Rosch, Nature Physics, 8, 301 (2012).
P. Milde, D. Köhler, J. Seidel, L. M. Eng, A. Bauer, A. Chacon, J. Kindervater, S. Mühlbauer, C. Pfleiderer, S. Buhrandt, C. Schütte, A. Rosch, Science 340, 1076 (2013).