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It has been predicted that topological magnon insulators are realized in kagome plane of pyrochlore magnetic insulators with Dzyaloshinskii-Moriya interaction. Bosonic topological insulators can exhibit a topological band structure. Although bosonic system ground state is trivial condensate or the vacuum, their excited states may carry signatures of the topology. In this presentation, I will show the distinct features of excitations in kagome lattice within the framework of the spin-wave theory: (a) finite lifetime at zero temperature due to spontaneous two-magnon decays, (b) the renormalization of magnon energy depending on the magnetization direction, (c) singularities in the decay rate. Those features are shown in the form of dynamical structure factors. Their effect in experimentally detecting edge modes will also be discussed.

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Yanbai Zhang, TU München (Visiting Scholar)
Zoom ( URL https://uni-koeln.zoom.us/j/92374710227 )
Contact: Matteo Rizzi