Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 41: Frontiers of Electronic Structure Theory: Focus on Topology and Transport I
O 41.6: Talk
Tuesday, March 8, 2016, 15:30–15:45, H24
Topological magnons: Any chance to find them? — •Alexander Mook1, Jürgen Henk2, and Ingrid Mertig1,2 — 1Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle — 2Institut für Physik, Martin-Luther-Universität, D-06120 Halle
Topological magnon insulators (TMIs) have a nontrivial topology due to the Dzyaloshinskii-Moriya interaction which results in spatially confined edge states and, thus, energy and spin currents along their edges [1,2]. Several systems have been identified as TMIs, for example, Cu(1,3-benzenedicarboxylate) consisting of kagome planes [3], or the family of ferromagnetic pyrochlore oxides, e. g., Lu2V2O7, showing the magnon Hall effect [4]. However, to date, no direct experimental evidence of a topological magnon band has been provided, what comes down to the small total width of the magnon dispersion relation and the energy resolution of surface sensitive measurements.
We propose Fe3Sn2 as promising candidate for a TMI. The total width of its magnon dispersion relation is large, and we determine its nontrivial topology by constructing an effective spin Hamiltonian. On this basis, we discuss signatures of topological magnon states that should be looked for in experiments.
[1] L. Zhang et al., PRB 87, 144101 (2013); [2] A. Mook et al., Phys. Rev. B 89, 134409 (2014); eidem, Phys. Rev. B 90, 024412 (2014); eidem, Phys. Rev. B 91, 224411 (2015); eidem, Phys. Rev. B 91, 174409 (2015); [3] R. Chisnell et al., Phys. Rev. Lett. 115, 147201 (2015); [4] Y. Onose et al., Science 329, 297 (2010).