  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.
