Phonon Dynamics in MnPSe3 Studied by Raman Spectroscopy and First-Principles Calculations

In contrast to well-studied sulfides in the category of van der Waals transition-metal phosphorus trichalcogenides MPX3, the intrinsic phonon properties of the antiferromagnetic semiconducting material of MnPSe3 remain unclear, which is crucial for exploiting its emerging applications. In this study, we present comprehensive angle-resolved polarized and temperature-dependent Raman spectroscopy measurements conducted on single crystals of MnPSe3, with the aid of group theory analysis and first-principles calculations. All of the experimentally observed Raman modes are systematically assigned. The thermal expansion coefficient for MnPSe3 is carefully determined using the quasi-harmonic approximation method. Further insight into the temperature-dependent red shift of phonon peaks and nonlinear broadening of line widths is obtained through a detailed theoretical model analysis, revealing their association with the anharmonic phonon-phonon interactions. Specifically, robust four-phonon scattering channels are identified, providing a deeper understanding of phonon heat transport in MPX3 materials.