Acoustic phonons in quasi-two-dimensional antiferromagnetic semiconductors revealed by Brillouin-Mandelstam spectroscopy

Interest in low-dimensional magnetic systems surged with the discovery of magnetism in some quasi-2D materials. While ferro- and ferrimagnetic compounds gained attention, antiferromagnetic semiconductors like Metal-transition phospho-trichalcogenides (MPX3) remained less studied. MPX3s are quasi-2D van der Waals semiconductors with diverse antiferromagnetic spin configurations. In this talk, I will describe the properties of acoustic phonons in such materials probed by Brillouin-Mandelstam inelastic light scattering. Acoustic phonons carry heat and contribute to electron–phonon, and magnon–phonon scattering processes. We observed significant variations in acoustic phonon velocities among materials with similar structures. Correlations with available thermal transport data underscore the importance of our findings for understanding layered vdW semiconductors. Authors acknowledge the NSF DMR project No. 2205973 “Controlling Electron, Magnon, and Phonon States in Quasi‐2D Antiferromagnetic Semiconductors for Enabling Novel Device Functionalities” and NSF MRI project No. 2019056 “Development of a Cryogenic Integrated Micro-Raman-Brillouin-Mandelstam Spectrometer.”