Strain-Induced Magnetic Phenomena and BKT Transition in 2D Transition-Metal Phosphorus Trichalcogenides

Few-layer transition-metal phosphorus trichalcogenides (TMPX₃) are emerging as promising 2D antiferromagnetic materials due to their ability to exhibit a wide range of magnetic behaviors. Depending on the transition metal ion, their magnetism can be described by the Heisenberg-like, Ising-like, or XY-like models, leading to rich 2D magnetic phenomena. In this talk, we present a first-principles study of the strain effects on the magnetism of TMPX₃ compounds, focusing on the resulting changes in symmetry and the underlying magnetic models. Furthermore, we explore the potential of TMPX₃ materials to support a Berezinskii-Kosterlitz-Thouless (BKT) transition—a phase transition at non-zero temperature predicted by the 2D XY model despite the Mermin-Wagner theorem.