Magnon-mediated Radiation and Phonon-driven Quenching of Excitons in a Layered Semiconductor

Abstract: Layered van der Waals (vdW) magnetic semiconductors open a new avenue for exploring intertwined excitonic and magnetic phenomena. Here, we investigate this interplay in the vdW MnPS3 antiferromagnet, uncovering an exceptionally long exciton lifetime (~100 {\mu}s) below the N\'eel temperature (T_N). We demonstrate that the exciton lifetime is governed by phonon-mediated nonradiative recombination and thus exhibits a strong temperature dependence. On the contrary, the radiative recombination rate shows a distinct temperature dependence, which is dominated by magnon-assisted emission mechanism below T_N and by short-range spin correlations and phonons above T_N. These findings not only establish MnPS3 as a compelling candidate for excitonic devices due to its long-lifetime and correlation with magnetic orders but also provide crucial insights into the interplay between excitons, spins, and lattice in vdW magnetic semiconductors.