Exciton-magnon splitting in the van der Waals antiferromagnet MnPS_{3} unveiled by second-harmonic generation

Abstract

Exciton-magnon pairwise excitation is promising to realize the direct and efficient photogeneration of magnons, especially in low-dimensional materials with large quasiparticle scattering cross sections. Using resonant second-harmonic generation spectroscopy, we identified exciton-magnon resonance in MnPS_{3} with possible splitting, in line with the exciton-induced modification of the magnon density of states based on our Koster-Slater-type theory. The substantial exciton-magnon interaction, favored by symmetry, sheds light on coherent cross control among charge, spin, and orbital degrees of freedom via quasiparticle correlations. Additionally, a large linear magnetoelectric effect of excitons is observed.