Hall 123

Theoretical and Experimental Observation of Topological Magnon in Honeycomb Ferromagnet CrI3

Solomon Owerre

Perimeter Institute

The original concept of topological band theory is rooted in electronic systems with strong spin-orbit coupling, possessing nontrivial bulk energy gap and topologically protected chiral edge electron modes. They are characterized by a topological invariant quantity such as the
Chern number or the Z2 index. In recent years, however, the concept of topologically protected bands has been generalized to bosonic quasiparticle excitations such as magnons, triplons, phonons, and photons. In this
talk, I will present the concept of topological magnon in honeycomb ferromagnets and also the concept of Weyl magnon in stacked kagome
antiferromagnets. Furthermore, I will discuss the first recent experimental realization of topological magnon in the honeycomb ferromagnet CrI3 without an external magnetic field. Lastly, I will introduce the Floquet theory as an alternative means to induce topological magnon modes in irradiated magnetic insulators such as the honeycomb-lattice Kitaev magnets.