Prediction of a Topological Magnon Insulator in a Two-Dimensional Chern Ferromagnet V₂WS₄ Monolayer

The Chern insulator (CI) and its bosonic analogue, a topological magnon insulator (TMI), are of considerable fundamental and technological significance in low-dissipation devices. Here, we put forward the possibility that the exotic CI and TMI phases can emerge within a single two-dimensional (2D) ferromagnet. Taking the square lattice as an example, the V₂WS₄ monolayer with a nonzero Chern number of C = 1 and the emergence of an electronic chiral edge state are employed as the material candidates to confirm the feasibility of our proposal. Moreover, the M_zC_4z^'-stabilized staggered alignment of the nearest-neighbor Dzyaloshinskii-Moriya interaction sustains an emergent gauge flux ϕ that breaks pseudospin time-reversal symmetry, thereby giving rise to the TMI with a nontrivial magnon Hall effect. This dual topology enables unprecedented cross-coupling of anomalous transport phenomena, offering a platform for interconversion spin and charge information with a high feasibility of applications in topological spintronics.