Evidence for Magnon-Assisted Exciton Radiation in a Layered Antiferromagnetic Semiconductor.

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 antiferromagnet MnPS_{3}, uncovering an exceptionally long exciton lifetime (∼100  μs) below the Néel temperature (T_{N}). We demonstrate that the exciton lifetime is primarily governed by phonon-assisted nonradiative recombination and thus exhibits a strong temperature dependence. In contrast, the exciton radiative recombination shows a distinct temperature dependence that is sensitive to magnetic order. Below T_{N}, the temperature dependence of the radiative recombination rate is consistent with a magnon-assisted emission pathway, while above T_{N} it reflects the combined effects of short-range spin correlations and phonons. These findings not only establish MnPS_{3} 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 lattices in vdW magnetic semiconductors.