Tuning bulk topological magnon properties with light-induced magnons

Although theoretical modelling and inelastic neutron scattering measurements have indicated the presence of topological magnon bands in multiple quantum magnets, experiments remain unable to detect signal of magnon thermal Hall effect in the quantum magnets, which is a consequence of magnons condensation at the bottom of the bands following Bose Einstein statistics as well as the concentration of Berry curvature at the higher energies. In a recent work, Malz et al.[Nature Communications 10, 3937 (2019)] have shown that topological magnons in edge states in a finite sample can be amplified using tailored electromagnetic fields. We extend their approach by showing that a uniform electromagnetic field can selectively amplify magnons with finite Berry curvature by breaking inversion symmetry of a lattice. Using this approach, we demonstrate the generation of bulk topological magnons in a Heisenberg ferromagnet on the breathing kagome lattice and the consequent amplification of thermal Hall effect.Ministry of Education (MOE)National Research Foundation (NRF)Published versionY.B. would like to acknowledge the support by the National Research Foundation, Singapore under the NRF fellowship award (NRF-NRFF12-2020-005). P.S. acknowledges financial support from the Ministry of Education, Singapore through MOE2019-T2-002-119