Lattice and Electronic Structural Evolutions in Compressed Multilayer MnPS₃

MnPS3, a novel ternary-layered material, hasattractedextensive attention in materials, physics, and chemistry owing toits excellent electrical transport and photoelectric properties. Pressureis a useful technique to explore unprecedented phenomena and propertiesin condensed matter. In this study, combining high-pressure Ramanspectroscopy, high-pressure absorption spectroscopy measurements,and first-principles calculations, the pressure-induced lattice andelectronic structural evolutions of multilayer MnPS3 wereuncovered. A pressure-induced lifted symmetry (layer sliding) of multilayerMnPS(3) from the C2/m-staggeredP-dimer phase (phase I) to P3 1m aligned P-dimer phase (phase II) at 6.7 GPa was demonstrated, evidencedby the overlap of E-g (5) and A(1g) (3) modes under high pressure and further first-principles calculations.Meanwhile, the linearly decreased optical band gap with pressure indicatedthat the charge-transfer excitations that define the gap were confinedin intra-slab in nature regardless of the interlayer sliding. Further calculated band gap structure also suggested that no obvious electronicstructural phase transition occurred in multilayer MnPS3 during the pressure-induced phase transition of multilayer MnPS3 except from a decreased band gap with pressure. In addition,both the results of absorption spectroscopy measurements and first-principlescalculation demonstrated that multilayer MnPS3 remainedto be a direct band gap semiconductor up to 21.8 GPa. Our findingsare of great significance in expanding the application of compressiveMnPS(3) in photoelectric devices.