Emergent multifunctionality in the two-dimensional Janus VSBrI monolayer: A study of multiferroicity, magnetoelectricity, and piezoelectricity

The Janus VSBrI monolayer, identified by first-principles calculations, emerges as a promising semiconducting material with desirable ferromagnetic and ferroelectric properties. Its in-plane magnetic anisotropic energy is up to $460\phantom{\rule{0.28em}{0ex}}\textmu{}\mathrm{eV}$/V, which is larger than many other known two-dimensional materials. The energy variations among different magnetic states show a strong correlate with polarization. Interestingly, the stability of the ferroelectric phase can be further enhanced by the application of biaxial tensile strain. The Janus VSBrI monolayer exhibits a notable out-of-plane piezoelectric response (${d}_{32}=1.60$ pm/V) due to its disrupted out-of-plane symmetry, a characteristic uncommon in Janus monolayers. These intriguing properties make the Janus VSBrI monolayer highly desirable for practical applications in piezoelectronic devices, and a promising candidate for multifunctional spintronic devices.