Structural, Magnetic, and Optical Properties of the van der Waals Antiferromagnet AgCrP₂Se₆

We have undertaken an extensive study of the structural, magnetic, calorimetric, and optical properties of AgCrP2Se6, a cleavable van der Waals material in the greater metal thio/selenophosphate family. We have found that this material exhibits a crystal structure of P3(1)12 and is antiferromagnetic below similar to 42 K, with spins pointed along the lamellar direction (i.e., the ab plane) rather than along the stacking direction. The magnetic saturation at 5 K is similar to 2.7 mu(B)/Cr. We note the presence of additional indicators of structural rearrangements at higher temperatures from calorimetric, powder diffraction, and Raman analyses, which suggest more complex and possible multiferroic behavior. Our optical reflectance measurements show an indirect bandgap of 1.240 eV and bright defect emission at 694.7 nm from the Cr3+ sites. Density functional theory calculations of both magnetism and the optical bandgap are in excellent agreement with experimental results. With its magnetic behavior and unique optoelectronic properties, AgCrP2Se6 appears to be a promising candidate for 2D device fabrication.