Magnetic structure and exchange interactions of the van der Waals CrPS4 monolayer under strain: A first-principles study

Intrinsic van der Waals layered magnets have attracted much attention. Herein, we carry out a comprehensive investigation of the air-stable two-dimensional van der Waals semiconducting magnet CrPS4 using first-principles calculations. With the first-principles linear response method and Monte Carlo simulations, we estimate the magnetic exchange constants and magnetic transition temperatures of both bulk and monolayer CrPS4. We find that the main intralayer interactions of bulk CrPS4 are all ferromagnetic coupling, while the dominant interlayer interactions of bulk CrPS4 are antiferromagnetic coupling. Using the calculated magnetic exchange constants, our Monte Carlo simulations show that monolayer CrPS4 has Curie temperature TC = 34 K. Moreover, we study the effect of uniaxial strain of monolayer CrPS4, and find that a uniaxial compressive strain greater than 6% along the b axis would cause the magnetic ground state to change into an up-up-down-down magnetic order along the b axis.