Magnon phonon hybridization in 2D antiferromagnet*

Magnons in magnetically ordered low-dimensional materials potentially enable novel nano-spintronics. The lifetime of magnons often depends on the strength of spin-lattice coupling and scattering with phonons. Here, we found coherent magnon phonon hybridization in the class of transition metal phosphorous trichalcogenides (MPX3, M = Fe, Mn, Ni and X = S, Se). From bulk to ultrathin layer, the antiferromagnetic magnons are identified by Zeeman splitting with applied magnetic field. A model is developed to quantitatively explain the nature of the emergent quasiparticles, as well as their center frequencies, scattering intensities, and polarization selection. This strong coupling may result in finite Berry curvature in the hybridization bands and possibly non-trivial topology.