Strain-Driven Switching of Easy Magnetization Axis in a Ferromagnetic Semiconductor LaBr₂ Monolayer

The precise manipulation of magnetic anisotropy in spintronic systems exhibits revolutionary potential for next-generation technologies. However, achieving deterministic control at the atomic scale faces critical bottlenecks due to the intricate interplay among spin-orbit coupling, interfacial symmetry breaking, and thermal fluctuations. Here, based on first-principles calculations, we demonstrate effective the control of the easy magnetization axis for the LaBr₂ monolayer by using strain engineering. The result shows that the biaxial compressive strain induces a fundamental transition of the easy magnetization axis from in-plane (<i>xy</i> plane) to out-of-plane (<i>z</i> axis). This change in easy magnetization axis stems from the strain-modulated orbital coupling between occupied and unoccupied <i>d</i>_<i>xy</i>/<i>d</i>_<i>x</i>²_<i>-y</i>² orbital states in La atom, which alters the energy splitting between competing magnetic anisotropy configurations. Our findings establish a viable pathway for engineering magnetic anisotropy in two-dimensional systems through lattice deformation, enabling potential applications in strain-controlled spintronic devices.