Strain-selected magnetic ordering in 1T'α-CrXY (X, Y = S, Se, Te) monolayers.

Two-dimensional magnetic materials have garnered considerable attention in recent years owing to their interesting phenomena and potential applications in spintronic devices. In this work, we report that the 1T'α-CrTeSe monolayer, where tellurium atoms are intermittently arranged line by line within the layer, exhibits strain-tuned magnetic properties. We find that the anisotropic nearest-neighbor exchange interactions in this monolayer result in a chiral helimagnetic state. The in-plane biaxial tensile strain suppresses the antiferromagnetic direct exchange interaction and leads to a transition from helimagnetism to ferromagnetism. Its transition temperature is estimated to be about 66 K and can also be tuned to near room temperature by applying strain. Furthermore, we also demonstrate the structural stabilities and strain-tuned magnetic ordering in the CrSeS monolayer. Our study provides not only an ideal platform to explore exotic compounds but also an important opportunity to design controllable magnetic materials in low-dimensional systems.