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.