Spin and lattice dynamics in the van der Waals antiferromagnet MnPSe3

Antiferromagnetic van der Waals family $MP{X}₃{{4pt}{0ex}}(M=Fe,{{4pt}{0ex}}Mn,{{4pt}{0ex}}Co,{{4.pt}{0ex}}and{{4pt}{0ex}}Ni;X=S{{4.pt}{0ex}}and{{4pt}{0ex}}Se)$ have attracted significant research attention due to the possibility of realizing long-range magnetic order down to the monolayer limit. Here, we perform inelastic neutron scattering measurements on single-crystal samples of MnPSe₃, a member of the MPX₃ family, to study the spin dynamics and determine the effective spin model. The excited magnon bands are well characterized by a spin model, which includes a Heisenberg term with three intraplane exchange parameters (J₁=-0.73 meV, J₂=-0.014 meV, J₃=-0.43 meV) and one interplane parameter (Jc=-0.054 meV), and an easy-plane single-ion anisotropy term (D=-0.035 meV). Additionally, we observe the intersection of the magnon and phonon bands but no anomalous spectral features induced by the formation of magnon-phonon hybrid excitations at the intersecting region. We discuss possible reasons for the absence of such hybrid excitations in MnPSe₃.