Control of magnetic properties of MnBi2Te4 using a van der Waals ferroelectric III2−VI3 film and biaxial strain

Using the first-principles calculations, we systematically investigated magnetic properties of a $\mathrm{MnB}{\mathrm{i}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ (MBT) monolayer in contact with $\mathrm{II}{\mathrm{I}}_{2}\text{\ensuremath{-}}\mathrm{V}{\mathrm{I}}_{3}$ two-dimensional ferroelectric substrates. As the electric polarization in the ferroelectric films is switched, a semiconductor to half-metal transition occurs in MBT, and its magnetic easy axis in several cases reorients. As an example, the Curie temperature of $\mathrm{MBT}/\mathrm{I}{\mathrm{n}}_{2}\mathrm{S}{\mathrm{e}}_{3}$ can be enhanced to 21.5 or 32 K under the influence of electric polarization and biaxial strain, much higher than that of the pristine MBT monolayer, which is 14.5 K in our calculations. Our results suggest effective ways to tune magnetic properties of MBT and provide useful insights for the further development of these important van der Waals functional materials.