Prediction of two-dimensional antiferromagnetic ferroelasticity in an AgF monolayer.

Two-dimensional multiferroics, simultaneously harboring antiferromagneticity and ferroelasticity, are essential and highly sought for miniaturized device applications, such as high-density data storage, but thus far they have rarely been explored. Herein, using first principles calculations, we identified two-dimensional antiferromagnetic ferroelasticity in an AgF monolayer that is dynamically and thermally stable, and can be easily fabricated from its bulk. The AgF monolayer is an antiferromagnetic semiconductor with large spin polarization, and with great structural distortion due to its intrinsic Jahn-Teller effect when thinning the AgF down to a monolayer. Additionally, it features excellent ferroelasticity with high transition signal and a low switching barrier, rendering the room-temperature nonvolatile memory accessible. Such coexistence of antiferromagneticity and ferroelasticity is of great significance to the study of two-dimensional multiferroics and also renders the AgF monolayer a promising platform for future multifunctional device applications.