Monolayer Bismuth Ferrite: Topological Antiferromagnetic Metal with Bimeron Spin Textures

The competition between dimensionality and ordering in multiferroic materials is of great interest for both fundamental physics and potential applications. Combining first-principles calculations with micromagnetic simulations, we investigate recently synthesized ultra-thin perovskite Bismuth Ferrite (BFO) films. Our numerical results reveal that, at the monolayer limit, the ferroelectricity of BFO is missing because the octahedral distortions are constrained. However, the monolayer bismuth ferrite is a topological antiferromagnetic metal with tunable bimeron magnetic structure. The dual topological non-trivial characteristics make monolayer bismuth ferrite a multifunctional building block in future spintronics devices.