Influence of strain on the magnetic and optical properties of monolayer XPS₃

Single-layer transition-metal thiophosphates (XPS₃) van der Waals magnets are promising candidates for high-speed and low-power-consumption information processing and storage devices. Based on first-principles calculations, we systematically investigate the biaxial strain modulation of magnetic and optical properties in monolayer XPS₃ (X = Mn, Ni). Monolayer MnPS₃ and NiPS₃ maintain their respective magnetic ground states of Néel-type and Zigzag-type antiferromagnetic (AFM) within the biaxial strain range of -9% to 9%, but show a tendency to transition to ferromagnetic ordering under increasing tensile strain. This is due to the dominant AFM couplings of the nearest neighbor J₁ in MnPS₃ and the third nearest neighbor J₃ in NiPS₃ being weakened. Further analysis of optical responses reveals that in the visible spectrum, the optical conductivity and absorbance of monolayer MnPS₃ are all enhanced under both compressive and tensile strains. In comparison, monolayer NiPS₃ exhibits a strain-driven redshift of its optical conductivity and absorbance peaks, with compressive strain amplifying and tensile strain diminishing peak intensities. This work provides a theoretical foundation for strain engineering of magnetic and optical properties in two-dimensional materials.