Noncollinear Antiferromagnetic Haldane Magnon Insulator

In this Letter we present a comprehensive study of topological magnon bands and thermal Hall effect in non-collinear antiferromagnetic systems on the honeycomb lattice with an intrinsic Dzyaloshinskii-Moriya interaction. We theoretically show that the system possesses topological magnon bands with Chern number protected edge modes accompanied by a nonzero thermal magnon Hall effect. These features result from non-collinearity of the magnetic moments due to an applied out-of-plane magnetic field. Our results provide an experimental clue towards the realization of topological magnon transports in honeycomb antiferromagnetic compounds such as XPS$_3$ (X=Mn,Fe) and $\alpha$-Cu$_2$V$_2$O$_7$.