Multiferroic Properties and Giant Piezoeletric Effect of 2D Janus WO3F monolayer

Abstract

Materials possessing both ferroelectricity and ferromagnetism are regarded as ideal candidates for electronic devices, such as nonvolatile memories. Based on first-principles calculation, we study systematically the crystal structure, electronic structure, magnetic, piezoelectric and ferroelectric properties of the two-dimensional van der Waals material WO3F monolayer. The WO3F monolayer is found to possess a robust square crystal structure, exhibiting exceptional stability and mechanical resilience. Magnetic characterization reveals that the material displays a ferromagnetic state with the magnetic moment of 1μB, alongside negligible magnetic anisotropy. In terms of ferroelectric properties, the WO3F monolayer demonstrates pronounced in-plane polarization, in stark contrast to relatively weak out-of-plane polarization, indicative of anisotropic polarization behavior. Additionally, the material’s piezoelectric response can be modulated through strain engineering, with the piezoelectric coefficient d11 at 4% tensile strain exceeding that of the vast majority of known 2D piezoelectric materials, underscoring its potential for versatile multifunctional applications in diverse fields including sensing, energy harvesting, and actuator technologies.