Metal Site Substitution and Role of the Dimer on Symmetry Breaking in FePS<sub>3</sub> and CrPS<sub>4</sub> under Pressure
Nathan C. Harms, K. Smith, Amanda V. Haglund, David Mandrus, Zhenxian Liu, Heung‐Sik Kim, J. L. Musfeldt
Abstract
We combine infrared absorption, Raman scattering, and diamond anvil cell techniques to explore the properties of FePS3 and CrPS4 under pressure, comparing our findings with a symmetry analysis, lattice dynamics calculations, and an examination of the energy landscape. Although these complex chalcogenides are considered to be members of the same family of materials, they display remarkably different phase progressions on account of the metal center orbital filling, character of the P–P linkage, layer corrugation, and differing size of the van der Waals gap. We discuss the space group progressions, structure–property relations, and development of pressure-induced metallicity in terms of the competition between local and long-range symmetry transformations and structural distortion pathways. These findings place the properties of FePS3 and CrPS4 on a firm foundation for work under strain control and in the single layer limit.